Souls of the Grey Council

Changeling (This card is every creature type.)

When a creature is played from any player's hand or dies on the battlefield, you gain 1 life.

{t}, sacrifice a creature: Put two 2/2 colorless clerics shapeshifter tokens into play. It has changeling.

"Being asked to serve on the Grey Council is a matter of soul, not flesh. The life I have experienced will not and should not matter, for I will have forgotten it." — A long-forgotten member of the Grey Council.