Libromancer Mystigirl

You can Ritual Summon this card with a "Libromancer" card. If this card was Ritual Summoned by using a monster(s) on the field, your opponent cannot target Ritual Monsters you control with monster effects. If this card is Special Summoned: You can target 1 face-up monster your opponent controls; until the end of this turn, change its ATK to 0, also negate its effects. You can only use this effect of "Libromancer Mystigirl" once per turn.

Fairy LIGHT Ritual Effect Monster 4 ritual