Byleth, Enlightened One

+2: Put one +1/+1 counters on up to two different Legendary creatures.
-1: Destroy target permanent with converted mana cost X, where X is the amount on +1/+1 counters you control
-8: You make an emblem "Each time a Legendary creatures enters the battlefield, put a +1/+1 counter on each Legendary creature you control"