Hydreigon

Dark

Hydreigon sports impressive Special Attack and decent Speed, allowing it to function as either a wallbreaker with Choice Specs, Expert Belt, or Life Orb to threaten balanced and defensive teams or a revenge killer with Choice Scarf to threaten more offensive teams. Its Dark / Dragon typing is amazing, having almost perfect neutral coverage against any type except Fairy. Hydreigon can also utilize its typing defensively coupled with its solid bulk, granting it the ability to switch into a handful of types comfortably. Thanks to Levitate making Hydreigon immune to Ground and entry hazards bar Stealth Rock, it's a particularly reliable switch-in to Ground-types. It also has a very diverse movepool with respectable coverage options such as Fire Blast and Earth Power to make it a more potent threat to a variety of types. Hydreigon also has access to U-turn to capitalize on its ability to revenge kill by gaining momentum. Hydreigon can also act as a stallbreaker thanks to its access to Taunt, Roost, and Devastating Drake, allowing it to prevent walls such as Toxapex and Mantine from recovering off damage and severely weakening them. However, it struggles to break through Fairy-types and suffers a huge weakness to them, making it depend more on teammates such as Greninja, Bisharp, and Alolan Muk to remove them. Hydreigon's typing also makes it difficult to deal with priority moves such as Ice Shard and Mach Punch from users such as Mamoswine and Breloom. Hydreigon's Speed is decent but sits below the crowded base 100 Speed tier, meaning it is outpaced by threats such as Mega Gardevoir and Volcarona without a Choice Scarf and outsped and revenge killed by faster Choice Scarf users such as Infernape, Latios, and Greninja. While Hydreigon's offensive stats are great and Speed stat is passable, it relies on Choice items to wallbreak or revenge kill effectively, making it more predictable and easy to counter. It has space for only one or two coverage moves, hindering its ability to take on a variety of types in the metagame.

Dragon

Hydreigon is a powerful special attacker for Dragon teams thanks to its solid offensive typing, extensive movepool, and versatility, being to utillze various items such as Choice Specs to act as a powerful wallbreaker and Choice Scarf to act as a potent revenge killer. Furthermore, Hydreigon is the only viable Dragon-type with access to a pivoting move, U-turn. This makes Hydreigon desirable to keep momentum for Dragon teams. However, while Hydreigon is a solid check to Ghost- and Psychic-types by typing, it has a crippling, compounded weakness to Fairy-types, as they resist its STAB moves. Hydreigon's moveset is also rather predictable on Dragon teams and can easily be scouted for. Lastly, despite having a good Speed tier, Hydreigon is outsped by powerful offensive checks such as Mega Gallade and Keldeo.