Revenant Banshee

Legendary Creature - Spirit

Eminence - Whenever another creature dies, if Revenant Banshee is in the command zone or on the battlefield, put a choir counter on it.

Counters remain on Revenant Banshee as it moves to any zone other than a player’s hand or library.

Remove all choir counters from Revenant Banshee: Revenant Banshee deals X damage to target player, and that player discards half X cards rounded down, where X is the number of choir counters removed this way. If it least one choir counter was removed, exile that player's graveyard and put a +1/+1 counter on Revenant Banshee.

3/4

Too much text, but whatever.

Wild.

Sorry, casting cost for The Village Bard should be .

The Village Bard

Legendary Creature - Human Bard

Whenever another creature enters the battlefield, you may pay . If you do, create a Treasure token.

: Exile The Village Bard and return him to the battlefield transformed.

2/1

Avenger of the Night ()

Legendary Creature - Human Warrior

First strike, menace

When Avenger of the Night enters, it deals X damage to each opponent and each creature they control, where X is the number of creatures that died this turn.

Whenever Avenger of the Night attacks, put a +1/+1 counter on another target creature.

3/4

My stab at the challenge.

Wild.

Isokai, One With the Blade

First strike, deathtouch, vigilance, trample

When Isokai, One With the Blade attacks, look at the defending player's hand and the top card of your library.

3/5

Repeat.