Nadaar, Selfless Paladin 
Legendary Creature — Dragon Knight
Vigilance Whenever Nadaar enters or attacks, venture into the dungeon. (Enter the first room or advance to the next room.) Other creatures you control get +1/+1 as long as you've completed a dungeon.
Legality
standardNOT LEGALpioneerLEGALmodernLEGALlegacyLEGALvintageLEGALcommanderLEGAL