When you planeswalk to Ketria and at the beginning of your upkeep, put your choice of a
vigilance (Attacking doesn't cause this creature to tap.),
menace (This creature can't be blocked except by two or more creatures.), or
trample (This creature can deal excess combat damage to the player or planeswalker it's attacking.) counter on target creature you control.
Whenever chaos ensues, exile cards from the top of your library until you exile a nonland permanent card. Put that card onto the battlefield or into your hand.