Latias

Latias's combination of typing, good offensive stats, bulk, coverage, and reliable recovery makes it one of the most dangerous and metagame-defining offensive presences in the tier. Access to Calm Mind as well as multiple usable Z-Moves takes this offensive prowess to the next level, allowing it to break through the majority of its potential checks, all while capitalizing on the defensive utility afforded by its good typing and high bulk for a fast offensive Pokemon. It also has access to key support moves in Trick, Healing Wish, and Defog to allow it to serve certain utility purposes as needed. All of this versatility makes Latias extremely flexible and team friendly and forces opponents to be on their toes until Latias has revealed its set to gauge their response accordingly. The tier has responded to Latias's presence, however, with a wide array of offensive and defensive counterplay: most faster Pokemon can heavily damage or outright KO it, it is vulnerable to common priority users like Scizor, Mamoswine, and Bisharp, and perhaps most importantly, it is weak to Pursuit from trappers such as Mega Aerodactyl and Krookodile. Furthermore, despite Latias's key resistances letting it exploit a good number of Pokemon, Dragon / Psychic does have its flaws as a defensive typing, as with six common weaknesses, Latias is forced out or Pursuit trapped by a large portion of the tier depending on its set. It is also heavily reliant on Z-Moves and the easily punishable Draco Meteor to do significant damage, as it is rather weak unboosted and can be easily pressured to fire off predictable attacks. Lastly, Latias's STAB combination is walled by Steel-types, meaning that it must either burn its Z-Move or sacrifice one of Calm Mind, Roost, or a Psychic-type attack to stand a chance against the likes of Empoleon, Mega Aggron, and Klefki on its own. These shortcomings open up Latias to relatively straightforward methods to minimize its impact on the game, meaning that while it is rare for any Latias set to be dead weight in a given matchup, there are many in which it will not be as devastating as it might otherwise be.