Necrosynthesis

Necrosynthesis (Necromancy)
Level: Mage 6, Necromancer 4
Mana: 35. Base Success: 60%.
Casting this spell imbues an undead with a permanent channel to the negative energy plane, allowing them to automatically replenish their form, regenerating 5 + 1 per 3 caster levels points of damage per round. This effect is permanent, and costs the caster [25 x Target's Challenge Rating] xp.