Majesty Maiden, the True Dracocaster (MACR-EN020) [Maximum Crisis]

To Tribute Summon this card face-up, you can Tribute a Continuous Spell/Trap Card you control, instead of a monster. Once per turn, during either player's turn, when your opponent activates a card or effect while you control this Tribute Summoned monster: You can add 1 "True Draco" or "True King" monster from your Deck to your hand.