Once per turn, if your monster would be destroyed by battle, you can send 1 "Therion" card or 1 "Endless Engine Argyro System" from your Deck to the GY instead.

Once per turn, when a monster is destroyed by battle and sent to the GY: You can target 1 "Therion" monster in your GY; add it to your hand.

You can only activate 1 "Therion Discolosseum" per turn.