3 Elminster An Azorius (white/blue) planeswalker for five mana, Elminster enters the battlefield with five loyalty, toting a triggered ability, a +2 ability, and a -3 ability, each of which synergize with each other in an impressive fashion
No flashy ultimate here, but her -2 is a seriously powerful way to get rid of an attacker
She has a triggered ability that, at the start of combat on your turn, places a number of +1/+1 counters equal to her power onto another creature you control, and permanently turns it into a mutant as well as its other types
"The flavor is fun, but a shield counter seems too good to give away for free." That didn't stop 1,137 players from building the deck, so perhaps I overvalued shield counters