Logistics (definitely, because a necromancer will limp along slowly with skeletons, meaning we need to be even faster), Wisdom (there are arguments like Explosion or Chain Lightning), Earth-Air as usual, and possibly Water. And Tactics, absolutely!
As for the Castle, humans seem decent (especially with expert water). Upgraded Crusaders can seriously disrupt the ranks, shooters can be protected thanks to tactics (and they deal damage very well), upgraded griffins are also no joke. If you solve the problem of Death Knights (skeletons will die from magic and troop attacks - archers+crusaders) - there's a chance.
And the main argument is the hero's high mobility, which makes it possible to plunder hives, conservatories, or maybe even the Dragon Utopia earlier!

Орден Феникса – харизматический :) лидер