Welcome to the forum, and the addiction!
As the games are only differentiated by key codes, it would be easy to cheat the receiving customer into buying a key-code the seller is still using - or after sharing it in the internet. Nonetheless, I hope you won't have any problems.
Enchantment is pretty good school. Reanimation gets you some undead rather fast, Behemoths are expensive but can really cause havoc, and later you would get Pale Riders (lots of Undead Horsemen, which are faster version of longdead) and a spell fitting Desert Tombs
very well - Reanimate Archers. Also, Raise Dead/Skeletons can be used to make whole armies to fight for you. Couple of Sauromancers or their Desert Tombs brethrens, or high-Death pretender alone, can raise enough to conquer whole independent provinces.
Evocation also has some interesting spells - Shadow Bolt and Shadow Blast are quite costly, but powerful. Cloud of Death isn't bad, either, and Bane Fire causes some heavy damage. Only few nations can get D3F1 casters, but as Desert Tombs, you'll really enjoy it. 53 damage, AoE 1, Range 40 for D3 caster... And for mages with Air or Astral, Winds of Death and Nether Darts are good. Remember that Nether Darts is much better than earlier Nether Dart, shooting 15 darts per casting.
Alteration has Drain Life, which is also very powerful.
And of course, Construction offers all kinds of interesting things. Skull Staff at Constr. 4 boosts Death, and at Constr. 6 you'll get Skullface and Flaming Skull.
For a good strategy, it's nice to have a pretender who benefits from the path you'll be researching. E.g. basic high-Death Prince of Death can summon lots of Undead Horsemen(Pale Riders), and high-Earth Cyclops lots of Enlivened Statues(Enliven Statues). If you go for Evocation, Fire or Water could work (Falling Frost, Falling Fires), but also e.g. Air and Astral (especially when combined with Fire) also work well.
Alteration can get you some pretty interesting spells, and powerful combatants really benefit from the combat boosts on the first 3-4 levels. With some Earth for Iron Skin, some Water for Quickness and some Air for Mirror Images and Mistform, you have one-monster-army. Fatique is a killer, and few hits will get through so you need as many hitpoints as possible. A combatant like that can do wonders for your early game. Search for SC to find out more.
SC is short from Saber Cherry. She's a regular poster, but while she was away newbies got to thinking the term originated form Super Combatant.
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Or not. But I always liked that theory more. And you wouldn't believe what she can do with her Math skills!
Endoperez,
Janne )`'´( Joensuu