Nate's Star Player
This week the Legendary Pokémon (according to the Pokédex) Arcanine gets the showtime!
Arcanine is one of the few Gen I Pokémon with OU potential...
1) Nice offensive stats, with 110 Attack and 100 Sp Atk
2) Decent defenses (90/80/80) and can be even bulkier if it's running Intimidate
3) A nice (and extensive) movepool, allowing the Legendary Dog to be either physical, special, mixed or even taking a defensive role and with new toys in this Gen like Close Combat and Wild Charge
...however, Arcanine is in the UU tier for a few reasons...
1) Being a Fire-type means it's vulnerable to the omnipresent Stealth Rock, taking 25% of its max HP every time Arcanine gets the switch-in not to mention it's weak to some of the most common types in the game, like Ground and Rock
2) 95 Speed is good, however most of the top threats in the metagame have 100 or higher Speed (for example Flygon, which is in the same tier as Arcanine has 100)
3) Some of the moves have drawbacks like recoil or lowering Arcanine's stats
Ability Compendium...
Intimidate: Allows Arcanine to take less damage from physical moves by lowering the opponents' Attack by one stage every time Arcanine gets the switch-in. Useless against special attackers or Pokémon with Clear Body, Hyper Cutter or White Smoke.
Flash Fire: Makes Arcanine's Fire-type moves more powerful if Arcanine is hit by a Fire-type move, while taking no damage from the opponents' Fire-type moves.
Justified: Increases Arcanine's Attack one stage everytime it's hit with a Dark-type move.
Recommended Ability: Either Intimidate or Flash Fire, depending of which role Arcanine has. Personally I'd go with Flash Fire since an immunity is nice, but Intimidate can save your life sometimes. Justified is very situational and unreliable but can still be used.
Arcana Force 0 - The Fool
@Life Orb
Ability: Flash Fire/Intimidate
Nature: Adamant
EVs: 252 Atk/252 Spd/4 HP
Flare Blitz
Close Combat
Outrage
Wild Charge
Important Note: Unless you want a dead Legendary Pokémon,
NEVER, ever try this set, though it is powerful enough to burninate the opponent's entire team, it will severely injure Arcanine in the process.
Flare Blitz is the STAB move of choice, no questions.
Outrage gets the infamous Fire+Dragon combination, hitting EVERY single Pokémon besides Heatran for neutral damage.
Speaking of Heatran, Close Combat takes care of the evil magma spider and those pesky Rock-types.
The three moves I mentioned before have 120 BP, but all of them have drawbacks balancing the attack power, Flare Blitz's recoil, Outrage's locking and self-confusion inducing effects and Close Combat's self-lowering defenses.
The last move hits Water-types, but hurts Arcanine in the process.
The nature and EVs maximize Arcanine's Attack, meaning more damage (and recoil from certain moves as well).
Life Orb makes Arcanine hitting like a rampaging Rampardos, but the recoil from the item (and the moves) will quickly reduce Arcanine's HP to critical levels, so
Leftovers can be used to mitigate the residual damage.
Flash Fire can increase Flare Blitz's power (and recoil), so
Intimidate is also an option.
Nate's recommended set
@Leftovers
Ability: Flash Fire/Intimidate
Nature: Hasty
EVs: Max Speed EVs, the rest can be invested in the offenses (more Sp Atk EVs than Atk EVs)
Flamethrower
Dragon Pulse
Wild Charge
Crunch
This set is more reliable than the suicidal set I mentioned before and a set Nate liked, though the attack power is severely lowered.
Flamethrower gets STAB and is more reliable in terms of power, accuracy and PP compared to Heat Wave and Fire Blast, not to mention Nate hates Flare Blitz's recoil effect.
Dragon Pulse grants the awesome Fire+Dragon coverage and because Nate is allergic to Outrage.
Wild Charge may hurt, but hits Water-types for super effective damage.
Crunch gets a surprising and nasty hit against Ghost and Psychic-types, not to mention the evil chandeliers of darkness will have trouble against that move.
Leftovers adds durability to the Flame Dog, but other items like the Choice items or Life Orb can be considered.