Sorcerer Necromancer

A necromancer is a Mage specialized in Necromancy school. Contrary to what some people think, most Necromancy spell don't affect only Undead (only a few do). Their spells all involve life or death in some variation. Necromancers have a broad range of spells - different types of damage, weaken enemy (debuff) or crowd control.

Unfortunately this does not exist in DDO, but a way to emulate it if you wish to play such a Mage for Role Playing reasons is to chose a sorcerer and only select necromancy spells. If you were to do that then the following feats and enhancements would be beneficial.

Usefulness of different feats
Spell focus is a good choice as it affects the degree of success of direct damage, weaken enemy (debuff) and crowd control spells.