Pestilence

Creatures your opponents control enter tapped.

Whenever a creature an opponent controls enters, you gain 1 life.

As this enchantment enters, choose a color.

Whenever a source of the chosen color deals damage to you, you may pay {1}. If you do, target player loses 1 life and you gain 1 life.

{1}: The next time a black source of your choice would deal damage to you this turn, prevent that damage.

All creatures are black.

Indestructible (Damage and effects that say "destroy" don't destroy this creature. If its toughness is 0 or less, it's still put into its owner's graveyard.)

At the beginning of the end step, if no creatures are on the battlefield, sacrifice this enchantment.

{B}: This enchantment deals 1 damage to each creature and each player.

({T}: Add {W}.)

Indestructible

As this creature enters, choose a player.

Whenever this creature is dealt damage, it deals that much damage to the chosen player.

{T}: This creature deals 1 damage to itself.

({T}: Add {B}.)

Level up {1} ({1}: Put a level counter on this. Level up only as a sorcery.)

LEVEL 6-11

6/6

Lifelink

LEVEL 12+

9/9

Lifelink, indestructible

Defender (This creature can't attack.)

Whenever this creature is dealt damage, you gain that much life.

Haste

Whenever a creature an opponent controls dies, put a +1/+1 counter on Yahenni.

Sacrifice another creature: Yahenni gains indestructible until end of turn.