Latios

With a combination of high Special Attack and Speed, Latios is a force to be reckoned with in the Doubles metagame. Boasting high power, Latios can severely damage or even KO a significant portion of the metagame with Draco Meteor alone. For an attacker, Latios sports good defensive typing, making it a good switch-in for notable Special attacks such as Mega Charizard Y's Heat Wave and Keldeo's Hydro Pump. Latios can also provide invaluable support by providing speed control in the form of Tailwind. However, Latios only has average bulk and is notably physically frail. Its strongest move, Draco Meteor, also has the nasty drawback of weakening Latios's power, meaning Latios is much less threatening once it's fired off the move. Lastly, Latios is easily switched in on and beaten by the numerous Steel- and Fairy-types in the metagame, such as Mega Metagross, Sylveon, Mega Gardevoir, and Mega Diancie.