Rebirth of the Seventh Emperors (MP24-EN361) [25th Anniversary Tin: Dueling Mirrors]

Tribute all Xyz Monsters you control, then target 1 of your banished Xyz Monsters; Special Summon it, then you can attach your "Number" Xyz Monsters that are banished and/or in your GY to it as material, that have a number between "101" and "107" in their name, up to the number of monsters Tributed to activate this effect +1. During the End Phase of the turn you activated this card, each player takes 300 damage for each card in their hand.