Etrata can't be blocked. Whenever Etrata deals combat damage to a player, exile target creature that player controls and put a hit counter on that card. That player loses the game if they own three or more exiled cards with hit counters on them. Etrata's owner shuffles Etrata into their library.

{T}: Add one mana of any color in your commander's color identity.

{2}, {T}: Copy target triggered ability you control. You may choose new targets for the copy. (A triggered ability uses the words "when," "whenever," or "at.")

{T}: Add {C}. {T}: Add {U} or {B}. This artifact deals 1 damage to you.

When this creature enters, you take the initiative. If a creature an opponent controls would die, instead exile it and put a hit counter on it. Whenever this creature attacks, if you've completed a dungeon, defending player loses 1 life for each card they own in exile with a hit counter on it.

Whenever a creature an opponent controls dies, exile it with a hit counter on it. Assassins, Mercenaries, and Rogues you control have deathtouch and "Whenever this creature deals combat damage to a player, you may remove a hit counter from a card that player owns in exile. If you do, draw a card and create two Treasure tokens."

Deathtouch Other Assassins you control get +1/+1. Whenever a player loses the game, if they were attacked this turn by an Assassin you controlled, you win the game.