Regarding magic schools.It all depends on the situation, the opponents, their upgrades, and the artifacts on the map.
Based on numerous experiments, I can say that light magic is the key. Resurrection and a huge mana reserve lead to victories without losses. Of course, this is in offline mode. I don't play online; I don't have the time.
Light.The most versatile magic. As a buff, it includes divine power (maximum damage), speed, punishing strike, evasion, and protection. It also includes resurrection, and teleportation sometimes helps. Regeneration is good with Rakshasa and Colossus in the early stages when there are few monsters; later, only resurrection is useful.
Summoning.It's good for clearing mines and artifacts up to level 10-15. It's not recommended to take it for the main hero, especially for the late game and serious battles. You simply won't have time to summon anything. Phoenixes will die in a couple of enemy turns, elementals won't deal much damage, phantoms will be destroyed immediately, crystals and sword walls are ineffective, as are mines.
Chaos.Honestly, it's funny. Without artifacts, witchcraft barely grows. I once had 18 knowledge and only 4 spells at level 15, even with a higher education! The hero was an Oracle.
Here's my experiment.




And here's a video: Oracle vs. 100 Seraphs.
http://zalil.ru/30799606Here's another one: Haffiz vs. Titans and Rakshasa.
http://zalil.ru/30799616Haffiz, by the way, was leveled up for his super ability; my emotions are so-so. I already had all the spells from the tomes and castles in my arsenal. Also, what I didn't like is that he can't train others, which makes it pointless. Level 24, and I can't properly upgrade any school.


If you equip yourself with artifacts, then yes, it makes sense. But again, it's better to take Nazira and attack with balls of energy, but you need a phoenix cloak, otherwise the damage isn't great, and Armageddon is also somewhat effective if you apply the magic sign.




I took ordinary units with resistance as cannon fodder.
You can carry Golems with magnetism and new units with increased damage, separate them before each battle into groups of 1, send them to the enemy, and attack with Armageddon or a ball of energy. More damage means more Golems can be restored. Dragons simply joined for cannon fodder.
Dark.Like light, it's effective. Subjugate one mob, berserk the neighbor; it has saved my life many times. Debuffs are my favorite, especially slow. Sometimes weaken is also useful. Although, if you separate 1 Djinn (ordinary), they debuff excellently for free, although with random spells.
Sorry for the off-topic.Here's my map from yesterday; only one enemy remains.

There's one useful tip for everyone: I found the best use for Golems. You should base almost any hero from the Shadow League on them.
Here's my example. I used him to clear half the map and kill 4 flags. The enemies had armies several times larger, but after a few enhanced Armageddons, no one could stand.




You can add Gargoyles to this and divide them into groups of 1 for each battle; it would be even more effective.
I'm uploading replays of the battles. The artifacts were a bit more modest. The witchcraft in the first video was around 18, then higher and higher.
http://zalil.ru/30799375http://zalil.ru/30799388http://zalil.ru/30799390http://zalil.ru/30799414Here's a really successful magical attack.
http://zalil.ru/30799429Here's something funny.
http://zalil.ru/30799443And this was a week of magic; all spells are twice as strong; look at the damage.
http://zalil.ru/30799451And this is just wild. A lucky strike + a week of magic. Look at the damage and be amazed.
http://zalil.ru/30799462http://zalil.ru/30799471This is the working damage.
http://zalil.ru/30799483Two lucky strikes.
http://zalil.ru/30799507And the last one against orcs.
http://zalil.ru/30799590And now, battles against the computer.Vayshan 28 lvl vs. Raven 24 lvl.
http://zalil.ru/30799543Vayshan 28 lvl vs. Zoltan 3 lvl (but with a large army).
http://zalil.ru/30799560And here, it's funny that fire elementals won't be saved from irresistible magic.
http://zalil.ru/30799576I also wanted to add something about mini-artifacts.
It's worth taking them at the last moment, although you can disassemble them back into resources.
I take 3 archmages for buffs; such artifacts are good for them:

I specifically made them have more initiative so that they go first; I immediately buff them with a punishing strike, and then use them as debuffers. For each hit, -3 protection. Destructive ray is free.
For attack, sometimes buff.

Titans have slightly less initiative, the rest is the same. For Djinns, spirit +4, attack +10, initiative +36%. For Goblins, attack +10, -3 protection per hit, +36% initiative. For Rakshasa, attack +10, +3 speed, +39% initiative.
And this is for ordinary Gargoyles; you could take protection or initiative instead of speed.

And this is Golems.

I'm waiting for questions; I'll be happy to answer and help! :)
Added 8 minutes agoYes, by the way, for those who play against the computer and suffer from unfair randomness, not the spell, they don't give the desired perk or skill, download HeroScanner 3.0, and you'll be happy.
You can also adjust the magic in the castle. Each "play again" gives new spells in the guild; you can scan until you get the ones you want. But it's boring and can be addictive. I used to only play with it, then I got bored. Without it, sometimes it's more fun, and sometimes it's not. If they don't give you what you're waiting for.