Ob Nixilis of the Black Oath

+2: Each opponent loses 1 life. You gain life equal to the life lost this way.

−2: Create a 5/5 black Demon creature token with flying. You lose 2 life.

−8: You get an emblem with "1B, Sacrifice a creature: You gain X life and draw X cards, where X is the sacrificed creature's power."

Ob Nixilis of the Black Oath can be your commander.