Yveltal

Yveltal is the most used Pokemon in SS Ubers and an essential part of the metagame. It is by far the most reliable check to Calyrex-S, with Calyrex-S having to rely on Trick, status, and passive damage to defeat it. It is the most common Defogger in a metagame sorely lacking them, and Yveltal's Knock Off limits switch-ins to the point that most teams have a dedicated Knock Off switch-in just for it. Utility options such as U-turn and Taunt give fantastic momentum, and Yveltal has useful revenge killing options in Choice Scarf sets, Sucker Punch, and Foul Play. Additionally, the right team support frees Yveltal up to use one of its devastating offensive sets; boosted by Hone Claws or Choice Band in addition to Dark Aura, Knock Off becomes a terrifying move to switch into. Overall, nearly every serious team should strongly consider having Yveltal.