Heren, Scavenger's student

You may cast spells from any graveyard, creature spells cast this way are a zombie in addition to their types, enter with a finality counter

Heren enters with a Trickery counter on him
When a spell you don't control that would make Heren leave the battlefield is cast you may remove a trickery counter if you do counter that spell

Creatures you control get +1/+1 for each unique creature type amongst creatures you control that it doesn't have (changeling counts for 1)