He Who Seeks, Steals, and Robs, Gabriel [Sword Art Online Animation 10th Anniversary]

[CONT] This card gets +1500 power for each character in your opponent's back stage. [AUTO] [(1)] When this card attacks, you may pay the cost. If you do, during that attack, perform a trigger check 2 times on the trigger step. [AUTO] [(1)] At the beginning of the encore step, if you do not have another [REST] character in your center stage, you may pay the cost. If you do, [REST] this card.