Krav, the Unredeemed

Partner with Regna, the Redeemer (When this creature enters, target player may put Regna into their hand from their library, then shuffle.)
{B}, Sacrifice X creatures: Target player draws X cards and gains X life. Put X +1/+1 counters on Krav, the Unredeemed.

Regna, the Redeemer

Partner with Krav, the Unredeemed (When this creature enters, target player may put Krav into their hand from their library, then shuffle.)
Flying
At the beginning of each end step, if your team gained life this turn, create two 1/1 white Warrior creature tokens.

Martyr's Bond

Whenever Martyr's Bond or another nonland permanent you control is put into a graveyard from the battlefield, each opponent sacrifices a permanent of their choice that shares a card type with it.

Liesa, Forgotten Archangel

Flying, lifelink
Whenever another nontoken creature you control dies, return that card to its owner's hand at the beginning of the next end step.
If a creature an opponent controls would die, exile it instead.