Developing a Necromancer hero.

The ideal Necromancer (in my opinion):

Super ability: all skills leading to it.
Defense: resilience, evasion, fight to the last.
Spellcasting: it depends on your preference, but the most important thing is to be an expert in spellcasting.

I wouldn't recommend skills leading to the super ability. There's almost nothing useful there for a Necromancer. Why would a Necromancer need banishment, for example? Or counterspell? All skills leading to the ability in the education branch are useless. The same goes for "Lord of the Dead" - it's nonsense. +1 to knowledge is only useful at the beginning of the game, not in the middle or at the end, when you already have a lot of knowledge. Defense. It's also unclear whether it's needed or not. Resilience and evasion seem useful, but "fight to the last" is only needed for Naadir. Spellcasting. It's also unclear why it's needed; it's better to take attack. So, I think this is far from the ideal build, although everyone has their own opinion.