This effect targets 2 Xyz Monsters either player controls. (You can also target 2 Xyz Monsters you control or 2 Xyz Monsters the opponent controls.)
This effect targets 2 Xyz Monsters whose Rank matches that of an Xyz Monster in the Extra Deck, except a “Number” monster. (This is performed using the sum of the original Rank of the 2 Xyz Monsters sent to the Graveyard. This effect cannot target monsters that can't perform the appropriate sum.)
The Xyz Monster Special Summoned by this effect is not considered to be Xyz Summoned. (It cannot be Special Summoned from the Graveyard afterwards by effects like "Monster Reborn.")
This effect does not negate effects that activate in the Graveyard.
If the activation or effect of this card is negated, the part of the effect that reduces all damage the opponent takes to 0 is not applied.
If 1 of the targeted monsters has already left the field when the effect of "Xyz Universe" resolves, since the part of the effect that sends both targeted monsters to the Graveyard cannot be performed, the part of the effect that Special Summons 1 non-"Number" monster from the Extra Deck is not applied. Furthermore, the part of the effect that reduces all damage the opponent takes to 0 this turn is still applied.