Knight of Obligation 
Creature — Human Knight
Vigilance
Extort (Whenever you cast a spell, you may pay 
. If you do, each opponent loses 1 life and you gain that much life.)
Legality
standardNOT LEGALpioneerLEGALmodernLEGALlegacyLEGALvintageLEGALcommanderLEGAL