Generation IV (Heatran) @ Power Herb
Ability: Flash Fire
EVs: 252 SpA / 4 SpD / 252 Spe
Timid Nature
- Magma Storm
- Solar Beam
- Taunt
- Stealth Rock / Toxic
Generation V (Keldeo) @ Choice Scarf
Ability: Justified
EVs: 252 SpA / 4 SpD / 252 Spe
Timid Nature
- Scald
- Hydro Pump
- Secret Sword
- Icy Wind
Generation VI (Volcanion) @ Choice Specs
Ability: Water Absorb
EVs: 72 HP / 4 Def / 252 SpA / 180 Spe
Modest Nature
- Steam Eruption
- Fire Blast
- Sludge Bomb
- Earth Power
Yeah this core is hot AF. Its kinda funny how they also happen to be 600 BST legends
Nerd: but Keldeo is 580 BST... Me: sssshhhh from three consecutive generations, but that's besides the point. This is a really cool offensive core due to just how many checks they share and are able to lure out+beat for each other. I wouldn't recommend this on anything other than heavy (not hyper) offense because their defensive synergy is fucking terrible, but offensively their synergy is really spectacular and very quickly leaves teams getting overwhelmed. Volcanion and Heatran break down fat grasses with their secondary STAB, Volcanion acts as this core's only stop to opposing Volcanion with Earth Power while also providing a check to non-HP Elec Keldeo and Azumarill with its good bulk, typing and access to Water Absorb (and Sludge Bomb just blows Azu back, which is also a thing). Keldeo lures out and weakens Latios while also acting as an offensive answer to Mega Lopunny and being able to RK Mega Manectric, Mega Beedrill, Mega Sceptile and anything else fast with Choice Scarf. It also beats or at least speed ties with Terrakion (depending on band vs. scarf) and stops pre-Polish Lando from ruining your day. Finally, Magma Storm+Solar Beam on Heatran allows it to trap and KO fat waters that give this core trouble, including (Mega) Slowbro/king,
Jellicent (big because literally hard walls both of the other two 'mons) and Taunt allows it to shut down and break through stuff like Chansey (especially if it carries Toxic>Stealth Rock) who gives this core trouble due to the fact that, outside of Secret Sword, it can very easily just abuse the other two members of the core.