You can only activate 1 card with this card’s name per turn.
(1) When your opponent activates a Spell/Trap Card while you control a “Magikey” Ritual Monster or a “Magikey” monster Special Summoned from the Extra Deck: Negate that activation, and if you do, destroy that card, then you can declare 1 Attribute, and if you do, all face-up monsters your opponent currently controls become the declared Attribute until the end of this turn.