[@Pyromaniacwolf]

Hard to put a limit on a power level, but depending on your magic proficiency

For something like a Necromancer, here's examples of power level

Novice: Resurrect a basic Skeleton, pretty weak, killed in a single hit
Adept: Resurrect multiple undead (Skeletons, fresh corpses, rotting corpses, etc) harder to take down (including animals like Bears)
Master: Resurrect pretty much anything, with a maximum of 15 humanoid corpses at once
There's a tier above master, reserved specifically for NPC's though