Kreme
You might be right but you're not correct.
Cobalion @ Shuca Berry
Ability: Justified
EVs: 252 Atk / 4 SpD / 252 Spe
Jolly Nature
- Iron Head
- Swords Dance
- Close Combat
- Stone Edge
+
Hydreigon @ Life Orb
Ability: Levitate
EVs: 252 SpA / 4 SpD / 252 Spe
Timid Nature
IVs: 0 Atk
- Taunt
- Roost
- Draco Meteor
- Dark Pulse
+
Azelf @ Life Orb
Ability: Levitate
EVs: 252 SpA / 4 SpD / 252 Spe
Timid Nature
IVs: 0 Atk
- Nasty Plot
- Psyshock
- Fire Blast
- Energy Ball
Ability: Justified
EVs: 252 Atk / 4 SpD / 252 Spe
Jolly Nature
- Iron Head
- Swords Dance
- Close Combat
- Stone Edge
+
Hydreigon @ Life Orb
Ability: Levitate
EVs: 252 SpA / 4 SpD / 252 Spe
Timid Nature
IVs: 0 Atk
- Taunt
- Roost
- Draco Meteor
- Dark Pulse
+
Azelf @ Life Orb
Ability: Levitate
EVs: 252 SpA / 4 SpD / 252 Spe
Timid Nature
IVs: 0 Atk
- Nasty Plot
- Psyshock
- Fire Blast
- Energy Ball
OK so basically this core aims to have two setup sweepers that support each other to ensure one or the other sweeps while a breaker is there to facilitate defensive synergy as well as aiding both in their endeavor.
First up, Cobalion. Cobalion provides a nice switch-in for Rock-types, and Dark-types among other things but it's mainly here for its sweeping potential and to act as a solid Mamoswine check. I chose a Stone Edge variant as this helped remove the ubiquitous Entei, as well as Salamence, which troubles the core somewhat. It also helps Cobalion remove the pressure on Hydreigon to deal with Chandelure.
Now, onto the main man himself, Hydreigon. I fucking love my Hydreigon lol, it's on most of my offense teams nowadays, and for good reason. On this specific core, however, it helps deal with Choice Scarf Chandelure, Swampert, Suicune, and the like. It's mainly here to simply act as good defensive utility for Scald and Fire-type attacks among other things but it also helps weaken the opposing team immensely, as well as ensure the opposing walls aren't able to recover any of their HP.
Lastly, Azelf. This Pokemon is a monster when it comes to sweeping from the special spectrum. The Nasty Plot set is extremely threatening and most things that stops the sweep are taken care of by other members (i.e Sucker Punch users, ExtremeSpeed users, Umbreon). Azelf has Energy Ball so that it can remove Swampert for Cobalion while also weakening Suicune and other bulky Water-types without the need to go into Hydreigon. Azelf also provides Ground-immunity alongside Hydreigon to pivot easier against the likes of Nidoqueen etc.
Now, as a final note. While it may seem like Hydreigon's just here to help the other two, those two also help Hydreigon break through stall by removing Florges (Cobalion Iron Head or +2 Azelf Psyshock), Blissey (Cobalion CC or +2 Azelf Psyshock), etc. Overall this is a very cool offensive core that's pretty fun to use.