(The basis of this set comes from the Hydreigon thread in the OU forums, particularly the idea of using Hydreigon's resistances, access to Roost, and 98 base speed to invest in bulk, while still hitting really hard. I know that Hydreigon's UU, and has been rejected for an OU Analysis, but it wasn't on the basis of this set, which gives Hydreigon a viable niche in OU.)
Hydreigon @ Life Orb
Ability: Levitate
EVs: 216 HP / 8 Def / 252 SAtk / 32 Spd
Modest Nature
- Draco Meteor
- Fire Blast
- Earth Power / Taunt
- Roost
Role: Bulky Attacker/Wallbreaker
What it does: Hydreigon's 98 base speed is a blessing in disguise, as the pokemon that Hydreigon is best suited to check sit at a much lower speed tier. This allows Hydreigon to run a bulky set, that has reliable recovery, while still hitting harder than Timid Latios. The introduction of fairy types has left Hydreigon with a new, exploitable weakness, but in return, the type changes have created a surge in Ghost and Dark type moves and pokemon in OU, making Hydreigon's Dark typing more valuable than it was in 5th Generation OU.
Max Special attack and a Modest nature allow it to hit as hard as possible, 32 Spd EVs outspeeds 252 Speed base 70s by one point (notably Bisharp and Breloom), 216 HP EVs hit a Life Orb number and give Hydreigon some bulk that complements Roost. This bulk allows Hydreigon to avoid being OHKOed by any priority moves (it survives Mach Punch from any Breloom set, and easily OHKOes in return), and allows it to check Bisharp, avoiding the OHKO from Adamant Life Orb Iron Head + Sucker Punch and most Aegislash sets.
Draco Meteor is mandatory as the nuke of this set, giving it a 50% change to OHKO 252 HP Rotom-W, and Fire Blast gives it coverage against Aegislash, Scizor, Mega-Mawile and Ferrothorn, all of which Hydreigon outspeeds. This leaves Hydreigon walled by Heatran, so Earth Power is the best move for the third slot. Earth Power also does 45.6 - 54% to standard Mega-Tyranitar, which with Stealth Rocks up, prevents it from switching in. Taunt is an alternative to prevent status hazards and setup moves from slower pokemon, and in conjunction with Roost, allows Hydreigon to beat Chansey 1 on 1.
Dark Pulse is also an option here, although with Fire Blast already on the set, Dark Pulse doesn't provide much additional coverage or power. Azumarill would then resist all three of Hydreigon's attacks and can set up a Belly Drum on it. Roost takes up the 4th slot, and allows Hydreigon to consistently check the aforementioned pokemon throughout the match.
Good Teammates: Hydreigon needs team members that can handle Fairy types, and that can handle the numerous powerful speedy attackers found in OU. Banded Talonflame, Offensive Deoxys-S, Thundurus, Greninja and Choice Scarf users . Hydreigon can also be used in conjunction with the popular Tyranitar + Sand Rush Excadrill core, as although it takes residual damage from Sand, as it can remove Rotom-W, and Ferrothorn, while Tyranitar can remove L@tias, and Excadrill outpaces the entire unboosted metagame - note that all these pokemon share a common fighting weakness that needs to be covered by the remaining three teammates. Aegislash appreciates Hydreigon's ability to handle Bisharp, and shares perfect type synergy with Hydreigon, resisting all of Hydreigon's weaknesses, and vice versa. Hydreigon can be used in conjunction with a number of offensive Mega Pokemon that appreciate Hydreigon's wallbreaking ability; for example Rotom-W is a common Mega-Pinsir counter, while Ferrothorn is a popular Mega-Gyarados counter.
What counters it: Firstly, pokemon that outspeed it and can hit it with a STAB super effective move are obvious checks and counters - there's quite a long list, but notably it would include L@tios, Keldeo, Mega Charizard-X, Terrakion and Greninja (not a guaranteed OHKO) - additionally, most Focus Blast users can OHKO it, although the 70% accuracy makes it a shaky counter to Hydreigon, as it is powerful enough to OHKO pokemon like Landorus with Draco Meteor if they miss. Hydreigon gained a big 4x Fairy weakness in Gen 6, making it vulnerable to Fairy type moves in general, although not many pokemon run fairy type coverage. Three common fairy types threaten Hydreigon; Sylveon has great special bulk, while Azumarill takes less than 50% from Hydreigon's common moves, although Azumarill will be forced to use Play Rough, as it cannot set up on Hydreigon with Belly Drum (Hydreigon easily survives a +6 Aqua Jet and can do over 75% with two Earth Powers, negating the Sitrus Berry). Mega Gardevoir can switch in and outspeed Hydreigon, but is physically frail and suspectible to revenge killing.
Assault Vest users can generally survive one of Hydreigon's attacks and strike back, although AV Conkeldurr cannot switch in, as it is actually 2HKOed by Draco Meteor. Special walls such as Chansey beat Hydreigon that lack Taunt.
Any additional info: This set seems like Hydreigon's best niche in OU - while Hydreigon does have access to an enormous physical and special movepool, Dragon, Fire and Ground moves allow Hydreigon to cover almost all of the pokemon that it outspeeds. Hydreigon does have access to U-Turn, but this is better suited for a Choice Scarf set.
