Astrid, Artful Throat-Slitter

When Astrid enters the battlefield, choose three creatures each opponent controls. That player
chooses one, and sacrifices it then returns the rest
to their hand.
Whenever a creature dealt damage by an Assassin
you control dies, put a +1/+1 counter on target Assassin you control and draw a card.
{b}{r}, {t}: Create a 1/1 black Assassin creature
token with shadow and deathtouch.