A 4/4 Vigilance for four mana is at least playable… sort of. And there’s quite a few knights available. I thought they were supposed to be rarer than soldiers?
Aryel, Knight of Windgrace
Legendary Creature – Human Knight
2W, T: Create a 2/2 white Knight creature token with vigilance.
B, T, Tap X untapped Knights you control: Destroy target creature with power X or less.