Undead Curse

All creatures you control gain "Undead" in addition to all their other types.
Every Undead creature you control has 3 "humanity" counters. Whenever a creature with a humanity counter would die regenerate them instead and remove a humanity counter. If a creature loses all of it's humanity counters it losses it's Undead creature type and gains the Hollow creature type instead.
"Stupid Undead, they can't even die right"-Hawkwood The Deserter