Evilswarm Exciton Knight (LVAL-EN056) [Legacy of the Valiant]

2 Level 4 monsters // Once per chain, during your Main Phase or your opponent's Battle Phase, if your opponent has more total cards in their hand and their side of the field than you do: You can detach 1 Xyz Material from this card; destroy all other cards on the field, also your opponent takes no further damage this turn (this is a Quick Effect).