Heroes 5.5 WarGame Edition - Tactical Edition.

What about vampirism? That's definitely not an undead spell.

Added 1 minute ago
And here's another point: don't you think runes are extremely overpowered?
I especially want to highlight the energy rune and the battle rage rune.

Well, why would it be an undead spell? Just based on the name? If anything, it's more of an anti-undead spell (considering things like mind control and plague, which necromancers love).
Vampirism isn't just about resurrection; it's also a good analogue for exorcism (removal) in the darkness. And that's exactly what undead don't need, because they're already immune to what vampirism provides. But dark elves, demons, or humans can benefit greatly from it. And as an analogue for exorcism, it's much more important for the first two races. And I think I've already written about this.

So, I'm not discouraging it, I'm just explaining why I can't accept such suggestions in my mod. Subjectively, they might be logical, but objectively, they impoverish the gameplay. After all, we're talking about banning such spells for heroes who are not undead, right? Although even this ban can be circumvented by hiring a necromancer for a living army and calmly using "undead" goodies (even in larger quantities with vampirism).