Charizard @ CharizarditeX
Ability: Blaze
EVs: 40 HP/252 Atk/216 Spe
Adamant Nature
- Swords Dance
- Flare Blitz
- Dragon Claw
- Roost/Outrage
Talonflame @ Choice Band
Ability: Gale Wings
EVs: 252 Atk/4 Def/252 Spe
Adamant Nature
- U-Turn
- Brave Bird
- Flare Blitz
- Tailwind
Feraligatr @ Life Orb
Ability: Sheer Force
EVs: 252 Atk/4 Def/252 Spe
Jolly Nature
- Dragon Dance
- Waterfall
- Crunch
- Ice Punch
This is obviously an offensive core composed with the aim of providing immense offensive pressure. Because all three have similar checks and counters, the general idea is to overload the checks and counters, most likely starting with Charizard X to nuke its switch-ins, allowing Talonflame and/or Feraligatr to come in and finish the job. Swords Dance Charizard X represents the pinnacle of power in OU, and everything that normally prevents Talonflame and Sheer Force Feraligatr from sweeping gets annihilated. We are talking max def Hippowdon, max defense Slowbro, max defense Suicune, max defense Rotom W, Mega Slowbro, Tyranitar, Skarmory, Heatran, Gliscor, Landorus-T - the list only ends at unaware Quagsire, for which you'd need Outrage to defeat barring crit, previous damage, or Flare Blitz burn (Dragon Claw does 39%-46% and therefore is only a guaranteed 3HKO). Fortunately, Talonflame's brave bird is a guaranteed 2HKO and Quagsire takes a big risk if it switches into Feraligatr if it isn't at full health.
Charizard is also necessary to combat Mega-Manectric, which otherwise gives most Dragon-Flying-Water cores significant problems (as does anything resembling boltbeam)
After Charizard inflicts the pain, the opposition will find it extraordinarily difficult to handle CB Brave Bird spam or the potential for a Feraligatr sweep.
Talonflame also comes equipped with U-Turn and Tailwind to help the rest of the team.
If you're not concerned with quagsire or choose to run outrage, then swords dance Talonflame is probably the better option