Moves
Flare Blitz is boosted by Sheer Force and STAB and 2HKOes most walls if not OHKOing them. U-turn is a great move for pivoting, as it scouts for the opponent's play and creates momentum for the user. Rock Slide hits Flying-types such as Gyarados and Dragonite while also being boosted by Sheer Force. Earthquake hits Steel-types and Rock-types, the latter of which Fire is weak to. Earthquake also hits opposing Fire-types super effectively without risking the miss with Rock Slide. In particular, after Stealth Rock damage, Earthquake OHKOes Mega Diancie, which Fire has a difficult time facing. Alternatively, Superpower is very useful so that Darmanitan does not have to take recoil against bulky Normal-type Pokemon. It also hits Air Balloon Heatran but misses out on the OHKO on other variants. Superpower hits almost the same types as Earthquake but is better against Dark, as it OHKOes Tyranitar, while being very spammable versus Normal as well.
Set Details
As Darmanitan is a Choice Scarf user, maximum Speed investment with a Jolly nature allows it to become as fast as it can possibly be. It allows it to outspeed Choice Scarf Landorus-T and Choice Scarf Hoopa-U and to Speed tie with Choice Scarf Kyurem-B. Sheer Force is used to boost the power of Flare Blitz and Rock Slide to make Darmanitan a potential wallbreaker. Running maximum Attack investment allows it to hit as hard as possible even without an Attack-increasing ability.
Usage Tips
Darmanitan should be used carefully to preserve its health, as it is prone to getting worn down by residual damage. Darmanitan can be sent out on the first turn to scout for the opponent's intentions then U-turn out. As it is a pure Fire-type, it is naturally weak to Stealth Rock, and as Flare Blitz has recoil, it should generally not be sent out with Stealth Rock on your side of the field. Darmanitan should avoid getting inflicted with status such as poison, which will heavily cripple its health. Paralysis is another huge status Darmanitan should avoid due to it quartering Darmanitan's Speed, which makes its Choice Scarf useless. Rock Slide and Earthquake are coverage moves and should only be used against Pokemon that are weak to them, as Flare Blitz will generally outdamage them, although they can be used to take out low-health foes to avoid recoil and preserve Darmanitan's health. Due to its amazing power, Darmanitan often forces switches, which you can predict and use U-turn on to gain momentum. Darmanitan can be used as a revenge killer to KO weaker Pokemon, but the user should be aware of Flare Blitz's recoil. Darmanitan can also be used as a wallbreaker due to its ridiculous power, although the recoil taken from Flare Blitz if it attacks bulky walls will reduce its sweeping chances.
Team Options
As Darmanitan is a Fire-type, a hazard-removing partner like Torkoal or Charizard is absolutely crucial. Torkoal in particular is a great partner due to its ability to set up its own Stealth Rock, which helps cripple opposing Pokemon by breaking Focus Sashes and dealing chip damage throughout the battle, helping Darmanitan take them out easier. Mega Charizard Y and Darmanitan work amazingly as an offensive core due to both having ridiculous offensive stats, and Mega Charizard Y's sun increases the power of the already ridiculously strong Flare Blitz. Mega Charizard Y also helps clear out Rock- and Water-types due to its access to Solar Beam, which makes Darmanitan even better as a late-game sweeper, and is immune to Ground-type moves, which Darmanitan is weak to and doesn't want to stay in against. Infernape has great Fighting-type STAB moves, which helps with Normal-type walls, such as Porygon2 and Chansey, as well as Rock-types, letting Darmanitan use Earthquake as its coverage move. Infernape can also be used as an offensive Stealth Rock setter. Entei heavily weakens the opposing team due to its great coverage, and tt also has access to Extreme Speed, which can KO weakened Pokemon. Furthermore, Entei running Iron Head helps deal with Fairy-types, as most of them have high HP stats, which causes Darmanitan to be worn down by Flare Blitz recoil and prevents it from freely spamming the move. Victini and Darmanitan can also be used together with one weakening the opposing team through its STAB attacks and the other cleaning up late-game. They both also create a nice VoltTurn core, as they can pivot easily due to their ability to force switches. Volcanion is immune to Water-type attacks, which Darmanitan is weak to. It can also burn opposing Pokemon through Steam Eruption, allowing Darmanitan to clean up. Choice Scarf Chandelure is another good offensive partner, as it OHKOes Slowbro with Shadow Ball after Stealth Rock damage. It also has access to Energy Ball and Hidden Power Ice, which can scare off the Ground- and Dragon-types that Darmanitan usually has problems with.