by Jolly Joker
It is important to note, that this guide was written for playing on very hard and impossible difficulty. Easier levels with more money and resources to start with allow a more aggressive style of play with more emphasis on early troop build-up, but it is strongly recommended to play at least on very hard and prefarably on impossible difficulty. If there is an abundance of resources and money as on the easier difficulty levels, the differences in built-up requirements for the different towns are obscured, although those differences are clearly part of the overall balancing of towns. For instance, it is rather obvious, that Dungeon has a great line-up with 3 flyers (6th and 7th level creatures included), 2 medium shooters and 2 grunts. Getting all creature structures on impossible difficulty is another matter. The Pillar of Eyes which gives Dungeon its 3rd level creature is a prerequisite for every creature dwelling thereafter. To build the Pillar of Eyes you need 1000 gold and 1 each of the six resources. On easier difficulties it is no problem to build this structure. On impossible difficulty you may find it impossible to build that structure in the first week, because with only a bit of bad luck you simply may not find a stack of every resource.
Inferno is no easy town to play. Having a fully built up town with all upgrades, you can recruit 2035 Hit Points per week, by far the fewest of all towns. (Rampart's got the most with a staggering 2650 HPs followed by Conflux with 2588, Tower with 2420 and Stronghold with 2370.) Furthermore your HPs are the most expensive. You have to pay 28090 gold + 4M for them, so the average HP cost you roughly 13.8 gold. (the average Rampart HP which is cheapest cost 10.05 gold, while the next most expensive after Inferno is Castle with 13.2 gold per HP).
Building up your town is not cheap either. To get all upgraded creature dwellings (including fort, tavern, castle and capitol) you need 95300 gold and among other ressources 62 Mercury. Only Castle needs more money (98500), while in the ressources department Rampart (65 Crystals), Dungeon (64 Sulfur) and Tower (61 Gems) are in the same league. A small plus is the fact that you don't need as much wood and ore as the other towns, 95 each (including fort).
Building every structure in an Inferno town cost 115300 gold which is the most expensive of all. On the other hand you need the fewest Wood (120) and the second fewest Ore (120). Unfortunately you need 86 Mercury, too, netting you 3rd place in the demand list for one of the four other resources (1st is Rampart with 95 Crystals followed by tower with 89 Gems).
Your heroes, the Heretic (magic) and the Demoniac (might), are worth a closer look. Both develop well balanced, with the Demoniac having a preference for attack and defense from level 2-9 and the Heretic a preference for spell power and knowledge. After that is exactly even for the Heretic, while the Demoniac has a small plus on spell power and knowledge. This balance between might and magic is reflected in the probabilities for gaining secondary skills. A typical level 19 Heretic will look something like 5 5 7 6, a typical Demoniac 7 7 5 5 (without any artefacts and locations visits).
The Heretic is the most versatile hero around and can in theory get EVERY secondary skill, including Necromany AND Leadership, while the Demoniac is only barred from acquiring Necromany. That doesn't mean, you will see every secondary skill with them.
For a Heretic the skills Estates, Leadership, Luck, Navigation and Water Magic are more or less out of reach, while Air Magic, Diplomacy, Logistics, Pathfinding, Resistance and Scouting will rarely present itself as an option. On the strong side are Ballistics, Fire Magic, First Aid, Intelligence, Mysticism (highest probability), Scholar, Sorcery and Wisdom (every Heretic comes equipped with it), the rest being thrown in with good probability.
Demoniacs will have difficulties to acquire Air Magic, Eagle Eye, First Aid, Intelligence, Luck, Scholar and Water Magic. They tend to Archery, Armorer, Artillery, Ballistics, Logistics (highest probability), Offense, Resistance, Scouting and Tactics with the rest being not out of reach. Note, that there is no skill, that every Demoniac comes eqipped with.
It is important to look at the probabilities for acquiring skills in the magic schools. Both heroes have the highest probability for Fire Magic, then Earth Magic, Air Magic and lastly Water Magic. The probabilities for the Heretic are slightly higher for any of the four. The average heretic will get Fire Magic virtually always and most often Earth Magic, too, while the Demoniac will get Fire Magic almost always and Earth Magic very often, too (albeit this might take some time), but you will be hard pressed to find Heretics and Demoniacs with Water or even Air Magic. As spells cast on expert level have a highly increased effect, it pays to have a closer look at fire and earth spells, because these are the spells, Heretics and Demoniacs will cast most efficiently.
You probably know, that it is VITAL to get the primary skills of your heroes up. What you maybe don't know, is, that until you have advanced Town Portal as a spell, YOU NEED AT LEAST TWO GOOD HEROES. One for exploration and conquering and one for the defense of your home base. One of the problems of playing on impossible difficulty is the fact, that you can't afford to take the experience, when finding treasure chests in the first week. This will leave your hero(es) at a disadvantage in primary skill advancement and acquiring of secondary skills. This means, you have to do anything possible to train your heroes. BATTLE EVERY FORCE, and be it only for 200 experience. Visit every location. Go for any Mills to get the extra 1000 (500) gold and the resources. Go for every artefact, but take only those that don't cost you money.
One of the plusses of the Inferno town is the ability to build a level five mage guild. The first level should be built as early as possible, because you don't want your heroes running around without any magic back-up and you don't want your Demoniacs running around without even a spell book to record spells that they may pick up in magic shrines. So if you hire a Demoniac, buy him a spell book first.
Inferno can't have all spells. The following spells won't show in an Inferno town: Bless, Ice Bolt, Death Ripple, Animate Dead, Frost Ring, Prayer, Magic Mirror, Summon Air Elemental and Summon Water Elemental. Which is a good thing, because they are all (with the exception of the Necro spells) Air and Water spells, which you won't get any proficiency in.
The first level fire and earth spells are quite useful and very important for the Inferno. For the moment it suffices to say, that because of the dangerously low hit point production of the Inferno its first priority is the conservation of HPs. That might seem redundant, but this is not the case, as Inferno has more means to achieve this goal than other towns, as we will see.
Curse, Bloodlust, Shield, Slow and Stone Skin are all first level spells with mass effect on expert level. Curse, Shield and Stone Skin will reduce the damage the opponent does to your units and are therefore most important, while Bloodlust and Slow will increase the damage you do and give you a tactical edge on the battlefield, respectively. Magic Arrow might come in handy in the first ten days of a scenario. These spells will be your only spells for a long time, because you won't have the necessary Mercury to build higher Mage Guild levels. If you have a second level Mage Guild and get Visions, use it freely on any wandering monsters you are reluctant to attack. You might discover, that some of them are willing to join.
With Blind and Berserk the school of Fire Magic offers two of the best battle spells. Cast on expert level, Blind will in effect paralyze the target, so you can hit it, without retaliation (conservation of HPs), while Berserk on expert level is the most devastating spell at all, because you not only can neutralize up to four enemy stacks for one turn, but those stacks will fight against each other, taking away counterstrikes and HPs and wreak havoc on any battle tactic the opponent might have had.
Sacrifice allows even heroes with low spell power to resurrect unbelievably high numbers of hit points, but the problem with that spell is having the right stack to sacrifice, when the right moment for it has come. The right stack is almost always the stack of Familiars, but the AI tends to target Familiars first. So it may happen, that you don't have any more Familiars, when the time has come to resurrect your Arch Devils, Efreets or Pit Lords. If this is the case, you might want to sacrifice Magogs.
Meteor Shower is quite devastating, if enemy stacks are adjacent to one another, while Fireball and Inferno may be useful in some situations, but only if your hero has lots of spell power.
The usefulness of the earth spells Town Portal, Resurrection and Implosion needs no futher explanation.
Armageddon is a special spell for you, because you have one of three creatures not afflicted by this spell (the others are Black Dragons and Gold Dragons, but Rampart town can't get Armageddon). See EFREETS on this.
With 15 gold per HP the Familiar is quite expensive. It is low on everything except speed, and the mana-sucking ability is useful only, if you are fighting against another hero and are low on spell points. The AI loves to kill them, so they are mainly cannon fodder. Grade the Imp structure up, if you can't afford to build a more expensive structure or have to save some money (usually in the second week). In most scenarios you'll have one or more Imp Crucibles somewhere on the map. Recruit them regularly (for free) and grade them up. 15 Familiars for 150 gold are a cheap decoy. Don't buy them in your town, until you have money left.
For a second level shooter this is not a bad unit. Unfortunately low level shooters are next to worthless in the first stages of a game, when you can't get them in high numbers and your hero is relatively weak. The range penalty halves the meager damage done, so the money is spend better elsewhere. Don't buy them, until you have money left. You won't need them in the beginning. With the beginning of the second week, when the Cerberus is available for you, consider leaving Gogs at home. With their low speed of 4 they only slow you down.
The Magog upgrade should be the last one you buy. Contrary to some people's believe the upgrade is quite good. You gain speed and attack value, and the area effect is useful, because in the mid- and endgame enemy heroes will be equipped with all kinds of war machines closing the gaps in their ranks. This allows targeting of ammo carts and first aid tents and so on and damaging the creatures left and right. The reason, why this should be your last upgrade, is the fact, that it costs 5 mercury. You need that mercury elsewhere.
On impossible difficulty this is the unit of choice for you. Kennels are a must-built in the first week (should be the first creature structure you build) and should be upgraded on the 1. day of the second week . They are fast, they have good attack and defense values, the enemy cannot retaliate and once in a while they can actually strike more than one stack. With 250 gold apiece they are reasonably priced (especially when compared to some of the other Inferno units).
Equip (one of) your hero(es) with the Cerberi production (two stacks of them seems to be best) of the first and second week (and Familiars, if you have them already, but nothing else) and move out with him. Flag every mine, fight against anything you feel you might have a slight chance to win. You'll be surprised, how effective they are, and losses will be minimal. Support all attacks with spells. You want as few losses as possible (think in terms of HP conservation). These Cerberi will be your main units for quite a while.
The backbone of your troops. Demons and Horned Demons are cheap solid hit points without special ability, but will give your hero the strength to fight against tougher creature stacks like all sorts of Golems, Elementals and fourth level creatures. You should grade them up, because the extra speed and HPs are worth it. As soon as you have Horned Demons, reinforce the Cerberi of your main hero with them.
Demons are of special importance for the Inferno because of the Pit Lords' ability to resurrect dead creature stacks as Demons (see below).
PIT FIENDS/PIT LORDS
Another expensive unit. You won't get the Pit Lord upgrade fast, because you need a 2nd level mage guild (4M) plus 5M for the upgrade itself, and you need the ressources for the Forsaken Palace. Don't buy Pit Fiends. They and their upgraded cousins are quite fragile with only 45 HPs and bringing in a few does no good. You don't want to lose them peacemeal, so horde them in your town and wait till the upgrade is available.
The special ability of the Pit Lords is not easy to use. To resurrect with them, the stack must have been completely killed (which is something you don't like at all), but if it's a stack of Familiars, no problem. Pit Lords resurrect HIT POINT-WISE, meaning they resurrect dead HIT POINTS as Demons, so after the resurrection you can't have more HPs than before. This means, 9 killed Familiars will resurrect to 1 Demon, which is not very impressive. Once you have Pit Lords in your force, you are well advised to organize your Familiars in stacks of numbers with multiples of 9, say 27. If you have free slots in your army, consider two stacks of Familiars. One stack should be a "sacrifice stack", with which to attack and take losses, so your Pit Lords are able to resurrect. If you do that, be sure the sacrifice stack gets wiped out, because if only 1 Familiar survives, your effort was wasted (and the Familiars are dead). This requires a lot of planning ahead, because you need a realistic view on how many losses the enemy will inflict to you in terms of Familiars, so you can built a sacrifice stack with the right quantity.
Another thing to keep in mind is the following: If you are in a battle that takes a more heavy toll and you lose some of your more important units like Efreetis or Devils, consider "kamikaze attacks" if only a few will survive to resurrect them as Demons and get the Hit Points back. For instance: Unfortunately a hard battle cost you 3 of your 4 Efreets. You should now try to lose the last Efreet, too, and then resurrect the whole stack. 4 Efreeti will be resurrected back to 10 Demons (if you have at least 10 Pit Lords and not resurrected before in this battle), so you will cut your losses on the HP front. If this ain't possible in rare situations there might be a chance to kill off one of your own stacks completely with the area effect of your Magogs. This is not easy to do, because the Pit Lords have to have a turn after your Magogs got their shot, and the enemy must not flee or be completely eliminated before the Pit Lords get their turn. So be careful here.
Any resurrection gives you cheap HPs for expensive ones, with one exception: If a stack of Demons dies, you can resurrect it without money losses, but this won't happen too often, and if it does, you'll probably lose the battle anyway. If not, you won't have enough Pit Lords to resurrect them all. Anyway, from a monetary point of view you should consider the following: If you have a free slot in your force, break down your Demons in two stacks. One stack should not exceed the number of Pit Lords you can realistically expect to survive the battle. This stack of Demons will be your sacrifice stack. Make first attacks with it to use up enemy counterstrikes. Then, if the stack has been killed, resurrect it. This is the most economical use of the Pit Lords' ability, but difficult to implement. So be warned. It takes some trying to get the feel for it.
On very hard difficulty you will try to get the Efreets in the first week, especially if the Hall of Sins is pre-built (in this case it might even on impossible difficulty not impossible to get them in the first week). Once you have Efreets, recruit them. Don't wait for the upgrade. You will save your Mercury for the Forsaken Palace, so you can't afford the upgrade, but you need the Efreets. With a speed of 9 they are fast, they have good HPs, they deal good damage and they are immune to all fire spells (NO BLIND, NO BERSERK, NO CURSE and, most important, NO ARMAGEDDON on them). So don't waste them. Efreet Sultans are attacked hand to hand only reluctantly because of their Fire Shield Defense, which deals 20% of the actual damage done to the Efreets (no excess damage, if all Efreets are killed) back to the attacker. So every enemy wants to use shooters and/or magic against them, which makes them a standout target. If you have got a decent number of them, don't wait, press the attack. Go for the enemy shooters, before they go for you.
If you have a hero with decent spell power and the Armageddon spell, consider taking an army consisting of seven stacks with one Efreet each with him. Remember, Efreets are immune to Armaggedon and Blind, so you can waste the enemy effortlessly by casting Armageddon, but don't take on forces with Black or Gold Dragons. This is by no means a foolproof tactic. If the enemy survives your first Armageddon strike, he might retaliate with Chain Lightning (might kill 3 or 4 stacks on average). Faster units like Arch Angels or Ghost Dragons might have taken out another stack, so you might have to flee. But you will blow away any mediocre army with no stack of massed HPs like a Horde Ogre Magi or Several Titans or a Pack of Dread Knights or something like that.
They have not many HPs. They are EXPENSIVE. They don't deal as much damage as the other 7th level creatures.
They have good attack and even better defense value. They are FAST. They reduce enemy luck. And the enemy can't retaliate.
Once you have the Forsaken Palace, consider recruiting them. A plague would be too embarrassing. You need every single one. Do everything possible to conserve them. If you have Resurrect or Sacrifice as a spell, you can use their speed and strike. Wreak as much havoc as possible, and if the enemy has attritioned them down, resurrect them. If you don't have any of theses spells, be more careful. Don't ever storm into the ranks of a strong grunt force like Fortress. You will see your Devils dead soon.
The tips and hints given here focus on L and XL maps under very hard and impossible difficulty. Smaller maps and easier difiiculty settings will concentrate more on troop raising.
If playing on impossible difficulty setting, you won't have any money or resources to start with (except you got the "bonus" there). So if you want to build something in the first turn you must move out with your hero and collect money and ressources. If you find a treasure chest, take the money. If you locate an Alchemist's Lab, take it immediately, if you have a decent chance. You need that Mercury desperately. On very hard difficulty you will recruit another hero on the first day and equip him or her with a spell book.
If you begin with two towns, concentrate the built up on one. Built a Town Hall in the second town as soon as possible, but then ignore the second town, until you have enough wood. Then build Mage Guild, Market Place, Blacksmith and City Hall. You can consider the further built-up of the second town, when you have conquered your first enemy town, but then it might be better to gon on with that conquered town instead, because it will be fully built-up already.
1. Mage Guild (buy spell book for any Demoniac)
2. Town Hall
5. City Hall
On very hard difficulty this is possible. On impossible difficulty you may have to change this sequence due to money and/or ressource shortages or even skip a build. The costs for these builds are: 13500 gold (+2500 gold for a second hero +500/1000 gold for spell book(s)), 25 Wood and 5 Ore, so you will have to find 3 resources stacks of Wood (plus a Sawmill) and some treasure chests and gold stacks. Don't forget, that you will need 5 Sulfur on the 8. day for the Upgraded Kennels. The minimum builds in the first week are Mage Guild, Town Hall, Kennels and Cages (7000 gold, 15 wood, 5 Ore). You should hire a second hero as soon as possible. A second hero to collect money and ressources will bring in the 2500 gold spent on him in no time and with interest. If you can get Fiona, hire her at any costs. Advanced Scouting will show you, where it pays to go, while her ability with Cerberi will strengthen you in the second week.
If you begin a scenario with the Hall of Sins already built, get the Demon Gate and the Fire Lake on days 6 and 7. On very hard difficulty you may go for the Fire Lake no matter if the Hall of Sins was build. This means, that you will be in need of money in the 2nd week, because you can't build the City Hall in the first week, so you have to go for the money fast and probably won't be able to build all creature dwellings in the 2nd week, especially because you will have to recruit 4 Efreets on the 8th day.
8. Upgraded Kennels (buy Cerberi; buy Efreets (only) if Fire Lake was built)
9. Upgraded Imp Crucible
10. Hall of Sins
11. Demon Gate
13. Fire Lake
14. Hell Hole/Castle
This might not work in full, because you won't have the necessary money and/or ressources, especially if you couldn't build on every day in the first week.Without the last build this will cost 12000 Gold, 5 Wood, 25 Ore, 3 Gems, 3 Mercury and 8 Sulfur. Because of the high Ore demand it might be impossible to build the Castle on the last day (10 more Ore). In this case the Hell Hole is a good alternative, because it costs no resources.
If you got the Fire Lake in the first week, go directly for Citadel, Castle and Capitol. Slip in the Hell Hole, if possible, but you don't need to build the Kennels if you are short on money and/or wood.
15. Upgraded Demon Gate
16. Hell Hole/Castle
Recruit Efreets (only). From now on you will save your money and ressources for the building of Capitol (if you haven't build it) and Forsaken Palace. In this third week you will have to make a vital decision: Building a Ressource Silo or not. You'll need that Mercury, but you'll need that 5000 gold, too. Decide depending on the situation. If playing on impossible difficulty, you won't get the Forsaken Palace until the fourth week, so you may not need Mercury that bad. If you built the Capitol in the 2nd week the Forsaken Palace is possible. Build it.
Order of Fire
With the Forsaken Palace up you now need more Mercury then ever, so the building of a Ressource Silo has to be seriously considered. You are now faced with the difficult decision, where to go. Every important outstanding structure needs Mercury to build, including the missing levels of the Mage Guild. As you need the second level Mage Guild for the Pit Lord upgrade, you should build it in any case. Those 4 Mercury are well invested there (and should be invested earlier, if enough Mercury is there). The Pit Lord upgrade is advisable, too, because those guys will help you lessen your HP losses. Then it depends. Going for the higher levels of the Mage Guild means taking a chance, because the spells may not be worth it. Getting the right spells on the other hand is better than the Arch Devil upgrade. Difficult decision, really.
If playing a small or medium map or a map full of resources under very hard difficulty you may try the following built-up:
1. Town Hall
2. Mage Guild
3. Hall of Sins
4. Demon Gate
5. Fire Lake
7. Citadel/Cages/Market Place
In the second week you'll upgrade the Kennels and build the missing structures for City Hall. This built-up will give you Efreets in the first week, but you may be in dire need of gold. The danger with this is, that the 4 or 5 Efreets you can buy at the beginning of the second week will make you over-confident. A gold mine guarded by a Pack of Crusaders could prove too hard to take and that would be the end of it, so be careful.
If battling light forces, your Devils and Efreets are strong enough to attack right away. However, if battling a force as strong or even stronger than yours, it most often pays to click all your stacks on wait to see, what the opponent does. The enemy shooters may strike, but as the range penalty applies, they won't do that much damage. Letting the slower enemy units move and casting (Mass) Slow in the right moment will give you in effect double turns for your whole force.
As mentioned before your first priority is the conserving of Hit Points in any battle, because you have precious few. Having and casting the right spells is most important, as stated in the spell section, and I will give a few examples here to underline this.
Ignoring the fastest units for the moment, you will have the opportunity to cast 2 spells, before a battle is in full swing. If dealing with 5 and more enemy stacks, consider the combination of Curse and Shield as a distinct possibility provided you a) have them and b) have them on expert level.
Example for the effects of that spell combination: Your force of 60 Cerberi and 30 Horned Demons (among others) faces a Castle force of 80 Royal Griffins and 40 Crusaders (among others). Let's assume, the heroes are roughly equal in strength and the enemy hero wastes his spells with, say, blinding your Magogs or doing damage with some Lightning Bolt or something like that. In the first round you cast expert Curse (mass effect), while dodging the enemy troops. In the second round you cast expert Shield (mass effect). The enemy shooters (Marksmen and or Monks/Zealots) will do damage in the first round, but not much. Curse will reduce the damage value of the Marksmen to 1 and Zealots to 9, and this damage will be halved because of range penalties. After the adjustments for Attack/Defense difference the damage will be minimal.
Okay, the Griffins now decide to attack your Cerberi. Without the Curse and Shield effects 80 Griffins would do between 240 and 480 damage (let's assume an Attack/Defence difference of 0), killing 9 to 19 Cerberi. With Curse the 80 Griffins do 160 damage. Shield reduces this damage by another 30%, so the 80 Griffins do 112 damage killing 4 Cerberi. FOUR. Now, that's harsh, isn't it? The heroes are roughly equal, and 80 Griffins can't kill more than 4 Cerberi. Just for fun let's determine, what the Cerberi do. In the first case 41 to 51 Cerberi retaliate (let's again assume A/D difference of 0) for 82 to 255 damage. They will attack again, when it's their turn and so the same damage again for no retaliation. So they will kill between 6 and 20 Griffins (compared to 9-19 killed Cerberi). In the second case 56 Cerberi retaliate for 112 to 280 damage and do the same damage when it's their turn to attack. So they will kill between 8 (most unlikely) and 22 Griffins this round. On average in the first case the number of dead Cerberi and dead Griffins should be roughly equal. In the second case you will on average kill 3-4 times as much Griffins than you lose Carberi.
Now the Crusaders attack the Horned Demons. With their double attack Crusaders deal awesome damage and are truly devastating. Normally 40 Crusaders would do 280 to 400 damage with their first attack (for simplicity let's assume again an attack/defense difference of 0), killing 7 to 10 Demons. The surviving 20 to 23 Demons would retaliate and do between 140 and 207 damage, killing 4 to 5 Crusaders (assume 5), and now the remaining 35 Crusader would hit again for 245 to 350 damage, killing another 6 to 8 Demons. Total loss: at least 13, at most 18 Demons. The remaining 12 to 17 Demons would now attack themselves and do between 84 and 153 damage, killing most likely 3 Crusaders, and the remaining 32 Crusaders would retaliate for 224 to 320 damage. Total loss for the Crusaders: on average 8. Total loss for the Demons: 18-26. No good.
With Curse and Shield the first attack of the Crusaders does 168 damage, killing 4 Demons. The remaining Demons retaliate for between 182 and 234 damage, killing 5 to 6 Crusaders (let's assume 6). The second hit of the remaining 34 Crusaders does 142 damage, klling another 3 Demons. Again, big difference: 7 Demons killed instead of 13 to 18. Now the remaing 23 Demons attack for 161 to 207 damage, killing 5, maybe 6 Crusaders with rest damage, but let's assume 5. The remaining 29 Crusaders do 122 damage killing 3 Demons. Total loss for the Crusaders: 11. Total loss for the Demons: 10. Kind of impressive, right?
The important thing is, that these spells work their magic for you in every single battle and every battle round, and beginning with the third round you can cast more spells, while your old ones are still in effect.
If you don't have Curse and/or are battling a force of Undead (Curse and mind-affecting spells like Blind and Berserk don't work with them), consider another strategy. (Mass) Slow in the first round will allow you to move virtually all your troops before the enemy. This means, if you wait with all your units in the first round, you can move twice with all your units, before the enemy can do anything. Casting (Mass) Slow in the first round and then (Mass) Shield in the second (provided the opponent didn't Blind your Devils or something equally nasty), will give you free reign on the battlefield. If not fighting Undead, Blind allows you to momentarily take out an enemy stack, but this spell is easily dispelled (and if dispelled in the wrong moment, it can be desastrous, so be careful).
When casting spells, the timing is all-important. If you cast (Mass) Slow or (Mass) Curse right away, and then the opponent counters with (Mass) Haste or (Mass) Bless, you have not only wasted a spell, but the opponent has the advantage. So follow this rule: If you want to cast a spell, wait until the last possible moment to cast it. The opponent may cast before you, and then you control the situation. (Mass) Slow is a spell, you should obviously cast as early as possible, but if the opponent decides to wait with his faster units, you can cast it easily later on in the turn. And even if he doesn't wait, the effect of the spell won't diminish, when you cast it a little later. The same holds true for (Mass) Curse. As long as the enemy can't reach you, you don't need to cast it, so wait.
The secondary skill Armorer should be chosen, if it presents itself as an opportunity, because the damage done by the enemy will be reduced by 5% per skill level, which will help you further in your effort to conserve Hit Points.
For the same reason, if you can choose between attack and defense skill, take defense. You need it.
If you can choose between spell power and knowledge, take the skill with the lesser value. Both values should be built up evenly. Spell power determines the duration of your spells and you'd like to see your spells last more than 1 or 2 rounds, while you need the knowledge to have the spell points available for extended casting.
INFERNO TACTICS AGAINST OTHER TOWNS
As opposed to Gorgons or Minotaurs or even Dendroids Pit Lords are NO tank troops. They are much too vulnerable and precious for that and should be kept in reserve to kill off lower level troops or hit on enemy stacks that won't retaliate anymore, because they have done so this round. Familiars have the same speed than Pit Lords, so they should be deployed left from the Pit Lords. Consider hitting a hard stack with Familiars first and then with the Pit Lords. Devils and Cerberi won't use up retaliation, so the only other viable stacks for that are Efreeti and Demons. Demons are slower than Pit Lords, so the Pit Lords would have to wait, which might be awkward in some situations.
Don't rush anything up. Your forces have good speed, which gives you a tactical advantage, and you need time to cast your spells.
It is possible to use Demons as your tank troops and attack very strong stacks with them to use up the retaliation. If you do that, MAKE SURE THE DEMON STACK WILL BE DESTROYED COMPLETELY IN THE BATTLE, because ONLY then your Pit Lords can resurrect them.
You might need a good logistic chain of heroes to a) bring fresh cannon fodder in form of Familiars to your front hero and b) take your resurrected Demons and go upgrade them.
If besieging a town, Inferno has the advantage, that their two strongest units are able to reach the enemy behind the walls right away. So lightly defended towns can be taken with Devils and Efreets alone.
With Berserk as a spell in your book and expert Fire Magic don't fear anything. Go ahead and conquer.
Don't rush anything. Cast your spells. If the Archangels attack right away, you have an easy target in the first round of battle. Heed the gesture of your Devils AND LET THE ENEMY COME TO YOU. Beware of the Crusaders. If possible, kill them with your Devils. Don't be too nervous about the shooters. As long as you stay out of range, they won't do too much damage. (Mass) Slow is an option to cast, especially considering the special ability of the Champions.
This is nasty. Dragons and Minotaur Kings are a real pain, there is no retaliation against Harpy Hags and the Evil Eyes and Medusa Queens are fairly strong shooters. Magic doesn't work against the Dragons, so there's no avoiding them. It's a good idea to kill the Dragons fast to deter the opposing Hero from casting Armageddon, if he or she has it. If you have seven stacks, the Dragons will have the opportunity to attack two, so you might want to battle them with only six stacks. If you have Tactics, position your units, so that there are no adjacent stacks. Use the Devils for the Minotaurs and Scopicores and bring down the Dragons with your grunts. Notice the effectiveness of Curse especially against Harpies and Minotaurs. Your Cerberi are quite effective against the lower level creatures, especially the Harpies.
Same as Castle. Don't rush anything. No shooters and no dangerous fast units. Fight Gorgons with magic. Cast (mass) Slow, rendering most units useless, then Blind Gorgons and Hydras, if the enemy wastes his spells. If dispelled, consider double turns with Devils and Cerberi (wait, then attack and retreat at the beginning of the new turn). Remember, Fortress has formidable defense values, so you have to attrition the units down.
Necropolis is immune against Curse, but is slow, too, so it's a good idea to slow them down more. Ghost Dragons are easily dealt with, but Dread Knights, Liches and Vampire Lords are a plague. Kill VLs with Devils, attack Skeleton hordes with Cerberi and then with Demons, avoid Dread Knights as long as possible and attack Power Liches in the second round. If you (Mass) Slow the opponent and then wait with your troops to get a double turn, don't forget to move your middle stack, so the Power Liches won't damage more than one stack. As this forfeits the turn for the middle stack, you should place the Familiars into this slot, if you don't have Tactics.
Rampart has no medium fast troops to speak of, so they either have to wait for their Dwarves and Dendroids or attack with Dragons, Unicorns and Pegasi alone. If they come to you, fine. If not, position your troops. Remember, if nothing happens in the first round, your Arch Devils will have the last turn and the first turn in the next round. Attacking the Elves and then immediately retreating again in the second round is not too bad. As with Dungeon you might want to bring in only six stacks because of the Dragons.
The Devils have to take on the Behemoths. Wait first, and then attack twice in a row without retaliation. Remember, Stronghold is strong on the attack, but weak in defense, so attacking pays dividends. (Mass) Slow works well. Your Cerberi are the ideal weapon against Wolf Raiders and Goblins, while your Familiars will be cannon fodder for Ogres and T-Birds to eat away the retaliation.
Press the attack! Tower has three shooters and can wait. The only real threat are the Naga Queens. No retaliation against them is a real pain, but you have no choice. Efreets are made for killing Genies, so go ahead and kill them. You might want to go on hold with your Devils and Efreets the first round to get your grunts upfront, but in general you have no time to waste.