Queen Marchesa

Deathtouch, haste
When Queen Marchesa enters, you become the monarch.
At the beginning of your upkeep, if an opponent is the monarch, create a 1/1 black Assassin creature token with deathtouch and haste.

"Tired of deceitful whispers and false alliances, Marchesa's rule now comes with a sharpened blade—those who challenge her will taste her wrath."