And I wouldn't assume that regeneration by default is only bypassed by acid and fire because mostly it's just trolls that work that way.
And actually necromancy doesn't just involve undeath, it involves the control over life and death. If you look at the necromancy school of magic you notice that there are many spells that don't raise undead, a lot of them kill people, affect their physical health or drain health and transfer it to someone else.Her use of "Necromancer" here is for lack of a better term. There's actually no "Real" undead involved (they count as constructs)
see thread title.