Undead Domain Cleric

This cleric class buffs the undead by granting them max HP  increase their AC  and most domain spells are undead or necrotic based. 

Undead Mastery

You need not cast animate dead or create undead every day to retain control,  you control them until they are destroyed.  The undead you animate or create have maximum HP.

Supreme Undead Master

Your power over undead is further enhanced as any created undead gain +2 HD +4 AC and +6 Con. 

Necromancy Savant

All Necromancy spells do +1 damage per dice rolled..