Ruthless Deathfang
Creature — Dragon
Flying
Whenever you sacrifice a creature, target opponent sacrifices a creature of their choice.
"Bring forth the dead, their skull-grins and rattle-bones. We will feast upon their wailing ghosts." —Silumgar, translated from Draconic
Filip Burburan
Rulings
Notably, the “legend rule” does not cause any permanents to be sacrificed. They are simply put into their owners' graveyards.
(wotc • 2015-02-25)
Ruthless Deathfang's triggered ability will trigger whenever you sacrifice any creature, including Ruthless Deathfang itself. It will trigger whenever you sacrifice a creature for any reason, including to pay a cost or as the result of a spell or ability (such as an opposing Ruthless Deathfang's ability).
(wotc • 2015-02-25)
Rulings
Notably, the “legend rule” does not cause any permanents to be sacrificed. They are simply put into their owners' graveyards.
(wotc • 2015-02-25)
Ruthless Deathfang's triggered ability will trigger whenever you sacrifice any creature, including Ruthless Deathfang itself. It will trigger whenever you sacrifice a creature for any reason, including to pay a cost or as the result of a spell or ability (such as an opposing Ruthless Deathfang's ability).
(wotc • 2015-02-25)