Immortal Obligation is a rare Instant card from Murders at Karlov Manor Commander (MKC), collector number 321. Current market price: $0.68, TCGplayer market prices via Scryfall.
Return target creature card from an opponent's graveyard to the battlefield under their control with a duty counter on it. For as long as that creature has a duty counter on it, it is goaded, can't attack you or a permanent you control, and can't block creatures you control.