Deathtouch (Any amount of damage this deals to a creature is enough to destroy it.),
haste (This creature can attack,
and
as soon as it comes under your control.)
When Queen Marchesa enters the battlefield, 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 (Any amount of damage this deals to a creature is enough to destroy it.) and
haste (This creature can attack,
and
as soon as it comes under your control.).