Altar's Reap

As an additional cost to cast this spell, sacrifice a creature.
Draw two cards.

Carrion Feeder

Carrion Feeder can't block.
Sacrifice a creature: Put a +1/+1 counter on Carrion Feeder.

When Doomed Traveler dies, create a 1/1 white Spirit creature token with flying.

Vigilance
Whenever another creature you control dies, you may transform Thraben Sentry.

Delve (Each card you exile from your graveyard while casting this spell pays for {1}.)

As an additional cost to cast this spell, sacrifice a creature.
Destroy target creature.

Whenever another creature you control leaves the battlefield, put a +1/+1 counter on Ninth Bridge Patrol.

When Hunted Witness dies, create a 1/1 white Soldier creature token with lifelink.