Target 1 "Magistus" monster you control; equip it with 1 "Magistus" monster, except a Level 4 monster, from your Extra Deck, GY, or face-up field. If you have at least 1 each "Magistus" Fusion, Synchro, Xyz, and Link Monsters in your GY, you can equip it with 1 non-"Magistus" Fusion, Synchro, Xyz, or Link Monster from your Extra Deck, instead. You can only activate "Magistus Theurgy" once per turn.