Guinevere, Queen of Hearts

Deathtouch, haste
When Guinevere, Queen of Camelot enters the
battlefield, you become the monarch.
At the beggining of your upkeep, if an opponent
is the monarch, create a 1/1 black Assassin
creature token with deathtouch and haste.
''And this damosel is the most valiant and fairest
lady that I know living...'' —King Arthur