
Vigilance
Extort (Whenever you cast a spell, you may pay {W/B}. If you do, each opponent loses 1 life and you gain that much life.)
Knight of Obligation has 1 printing, first in Gatecrash (2013). EDHREC ranks it #21,096 among Commander cards. It appears most in The Kingpin of Crime decks (87 on EDHREC). It has 4 official rulings.
Deck counts from EDHREC.
Cards that show up in the same decks on EDHREC.