Questions about the gameplay of Heroes 6.

Is the hero perhaps a Necromancer? I also tried to apply it to undead creatures, but to no avail. It seems ideologically impossible. However, I'm currently only leveling up Blood skills. And I don't think it can have any effect other than a quantitative one.

Yes, he is a Necromancer. Anastasia in the campaign. I think if it were ideologically impossible, then the skill and its upgrade shouldn't be available, or is this just another bug? I also think that the chosen path gives quantitative characteristics to the skills.