Mono-fight is probably my fav mono teams of all time, so I can give some advice based on past experience.
Conkeldurr @ Leftovers/ Flame Orb
Ability: Guts
EVs: 252 HP, 252 Atk, 4 SDef
Nature: Adamant
- Bulk Up
- Mach Punch
- Ice Punch
- Drain Punch
Guts > Iron Fist. In fact, Guts > almost any ability. Guts is a really great ability that will mean your Conkeldurr won't be useless when burned by stuff like Rotom-W. You can give it Flame Orb to activate Guts, or Leftovers to try and fool your opponent into thinking it has Iron Fist.
Scrafty @ Leftovers
Ability: Shed Skin
EVs: 252 HP, 252 Sp. Def, 4 Def
Nature: Careful
- Bulk Up
- Rest
- Drain Punch
- Crunch
This is the better Shed Skin/ Rest set. I would not give Scrafty Shed Skin and Dragon Dance, simply because if Scrafty doesn't wake up ASAP, it'll get KO'd. Bulk Up will mean it has a much larger chance of surviving.
Breloom (M) @ Focus Sash
Ability: Technician
EVs: 252 Atk, 252 Speed, 4 HP
Nature: Jolly
- Mach Punch
- Bullet Seed
- Spore
- Swords Dance
Classic TechniLoom (my fave Breloom set), not much else to add. You're pretty much screwed, though, if you're facing a sand/ hail team. Also watch out for Magic Bounce, since your opponent will almost always predict Spore.
Terrakion @ Choice Band
Ability: Justified
EVs: 252 Atk, 252 Speed, 4 HP
Nature: Jolly
- Earthquake
- Close Combat
- Stone Edge
- X-Scissor
I would rather give Terrakion a Band, just so it gets that monstrous attack boost. At base 108, it outspeeds a lot in OU.
Lucario @ Focus Sash
Ability: Justified
EVs: 252 Spd / 96 HP / 160 SAtk
Nature: Modest
- Nasty Plot
- Aura Sphere
- Dark Pulse
- Vacuum Wave
Hmm, I guess Lucario fulfills your special attacker role, but I don't use it that much due to how frail it is.
Sawk @ Choice Scarf
Trait: Sturdy
EVs: 252 Atk / 252 Spd / 4 HP
Adamant Nature
- Close Combat
- Earthquake
- Stone Edge
- Dual Chop
(see below for comment on Sawk)
- Sawk is not good for OU environment. A lot Pokemon outclass it in nearly everything. It's a good NU Pokemon, just not suitable above RU.
- I do not recommend having Lucario, Terrakion and Scrafty all on the same team. They are all weak to Fighting.
- I don't like Conkeldurr much as a Pokemon, but that's just a personal thing. It's just too slow to get any sweeping done without Trick Room support.
So here are my suggestions:
- Replace Conkeldurr with Heracross
- Replace Lucario with Keldeo
- Replace Sawk with Toxicroak/ Medicham
Heracross @ Choice Scarf
Ability: Guts/ Moxie
Nature: Adamant
EVs: 252 Atk, 252 Speed, 4 HP
- Close Combat
- Megahorn
- Stone Edge
- Sleep Talk
Sleep Talk = your Spore absorber, in case you face another Breloom. Guts or Moxie, depending what suits your fancy. Personally I got for Guts just because that's the safer option, but you can keep sweeping up with Moxie.
Keldeo @ Choice Specs
Ability: Justified
Nature: Timid
EVs: 252 Sp. Atk, 252 Speed, 4 HP
- Surf
- Secret Sword
- Icy Wind
- HP Ghost
Keldeo should be Uber imo, being one of the few Fighting types that's a special attacker with a decent enough movepool to do substantial damage. Chansey can cry when facing Spec'd Keldeo. I prefer Surf > Hydro Pump, for 100% accuracy and higher PP.
Icy Wind is the only Ice move Keldeo learns, and is good for stuff like Landorus, Salamence and Gliscor. It won't OHKO a Dragonite with Multiscale though.
HP Ghost is to deal with Jellicent and Celebi. Though be warned, while HP Ghost will do good damage, it will take at least a 2HKO for either of them.
Toxicroak @ Black Sludge/ Focus Sash
Ability: Dry Skin
Nature: Jolly
EVs: 252 Atk, 252 Speed, 4 HP
- Swords Dance
- Sucker Punch
- Drain Punch
- Ice Punch
Good thing about Toxicroak is Sucker Punch. Focus Sash will mean that it can set up at least one Swords Dance and proceed to sweep. Rain teams are also very common in OU, so Dry Skin will help it out.
Medicham @ Choice Scarf
Ability: Pure Power
Nature: Adamant
EVs: 252 Atk, 252 Speed, 4 HP
- Hi Jump Kick/ Drain Punch
- Ice Punch
- Trick/ Thunder Punch
- Psycho Cut
So while Medicham looks like a mediocre Pokemon with rubbish stats compared to most OU mons, but its saving grace is its ability, Pure Power. When Scarfed, Medicham can outspeed a lot, even in OU, with a passable base speed of 80.
