Arceus

With a strong priority move, fantastic 120 base stats across the board, and a wide array of coverage moves, Arceus makes for an effective late-game sweeper that can easily set up and sweep once its checks and counters have been weakened. However, a huge part of Arceus's viability also comes from its ability to serve as a very strong revenge killer for its team, taking out weakened offensive threats with its Life Orb Extreme Speed. Arceus also pairs well with other offensive behemoths such as Primal Groudon, Xerneas, Darkrai, and Mega Salamence, easing its ability to fit onto offensive teams. Arceus fares well against a variety of offensive threats due to having a strong priority move in Extreme Speed and various coverage options. Arceus also appreciates the decline of Will-O-Wisp support Arceus, non-Primal Groudon, and Landorus-T in the generation transition, competent checks in XY. However, a new check in Mega Salamence has been introduced, and old checks such as Mega Gengar are still troublesome.