Darmanitan just so happens to have the highest Attack stat of any Fire-type in the game, making it a great choice for sun teams. Sheer Force is a useful ability on Darmanitan that works well in tandem with its main STAB move, Flare Blitz. Combine all that with Drought support, and Darmanitan can flat-out OHKO almost anything that takes neutral damage from Flare Blitz and even some that do resist it.
Unfortunately, rain neuters Darmanitan's Fire-type STAB and makes it more susceptible to Water-type attacks. Darmanitan's Stealth Rock weakness is quite an annoyance as well, chipping away 25% of its health each time it switches in. The combination of Flare Blitz recoil, Life Orb recoil, and possibly residual damage from sandstorm, hail, or Toxic wears down Darmanitan fast. One of its biggest faults is its poor bulk, which means that Darmanitan cannot switch into much and has to rely on free switches to get in safely. Regardless of these setbacks, Darmanitan is a tremendous force to be reckoned with in sun and is always something you have to watch for in Team Preview.
A Choice Scarf turns Darmanitan into a merciless revenge killer and potential sweeper. As Darmanitan is cursed with below-average Speed, a Speed boost is much appreciated, allowing Darmanitan to comfortably use an Adamant nature without having to worry about being outsped by a larger portion of the metagame. Flare Blitz is Darmanitan's main STAB, which nukes anything that decides to stay in on it. Flare Blitz hits extremely hard with the boosts from Sheer Force, STAB, and sun, OHKOing most of the unresistant tier. Superpower is a really important weapon to have against Heatran and Tyranitar, which can comfortably wall Darmanitan, even in the sun. Rock Slide is used to hit Salamence, Gyarados, and Dragonite hard outside of sun while providing all-around better coverage against Flying-types. U-turn is used to gain momentum against Darmanitan's common switch-ins, such as Politoed and Heatran. U-turn also works well with Dugtrio as a partner, as Darmanitan can use U-turn on Heatran and go out to Dugtrio, which can trap it.Team Options & Additional Comments >>>
This set defines power. Actually, it does not just define power, it created the word power itself. Some might say Victini is an all around better physical sun attacker because of the insane power of V-create and its all-around better bulk and Speed tier. This, however, is far from the truth. A Life Orb-boosted Flare Blitz is actually stronger than Victini's Choice Band V-create, which says a lot. Flare Blitz is Sheer Force-, Life Orb-, STAB-, and oftentimes sun-boosted; nothing can tank it easily. Even physically defensive Jellicent is 2HKOed in the sun after Stealth Rock! The same goes for Gliscor, Rotom-W, and Latios. Here are some calculations that prove just how powerful this move is, factoring in a sun boost, Stealth Rock damage, and an Adamant nature:
Not even defensive Jellicent and Tentacruel, both of which are commonly used to wall Fire-types, can switch into Darmanitan. If you want a Pokemon that can KO half the tier, you have found it! Choice Band secures the 2HKO on physically defensive Jellicent and Politoed, though Darmanitan still has enough power with Life Orb. Superpower is one of the most important moves in the set because it wrecks both Tyranitar and Heatran. Rock Slide can be useful for taking out Dragonite and Gyarados in the rain or neutral weather. Earthquake is to hit Tentacruel outside of sun harder than anything else. U-turn is a great move to maintain momentum, as although Flare Blitz can decimate most of its switch-ins, U-turn is helpful for obvious Politoed switch-ins.Team Options & Additional Comments >>>
Darmanitan actually possesses somewhat decent support moves, such as Toxic, Will-O-Wisp, and Encore. The problem is that Darmanitan is so frail that wasting a turn using one of these moves often leaves it KOed. Taunt is a decent choice on the Life Orb set, but it requires some prediction to use and wastes a valuable moveslot that could have been used for extra coverage. A Bulk Up set sounds tempting, but even at +1 Darmanitan is still very frail. A Substitute + Salac Berry + Belly Drum set is somewhat of a gimmick, but if you manage to pull it off, pretty much nothing can stop Darmanitan from KOing everything in existence. Sleep Talk is actually not that bad of a move on Darmanitan's Choice sets to check Breloom and other Spore users.
Checks and Counters
The set you're going up against determines how hard or easy it is to counter or check Darmanitan. As Darmanitan primarily run Choice Scarf or Life Orb sets, it is quite easy to figure out what it is likely to be running based on the Team Preview or how often it has switched in. The Choice Scarf set is probably the harder of the two to deal with, especially when it is used on a sun team. It's not only fast, but also very powerful, so it's not easy to check or counter. Since most defensive checks are 2HKOed by sun boosted Flare Blitz, your best bet at properly checking this Darmanitan is by changing the weather with a Politoed, Tyranitar or Hippowdon. Defensive Politoed is capable of neutering Darmanitan's offense with Drizzle and can take pretty much anything Darmanitan throws at it. Tyranitar is another great check because it takes away sun upon entry while comfortably taking Flare Blitz (though it must be wary of Superpower) and threatening it with its powerful Pursuit. Physically defensive Hippowdon risks getting 2HKOed by Darmanitan's Flare Blitz, but it can change the weather in order to give its teammates the opportunity to avoid getting 2HKOed by Darmanitan's Flare Blitz. Heatran is a great check to the Choice Scarf set, but it must be cautious of Superpower. Defensive Jellicent is rarely 3HKOed by Flare Blitz outside of sun, and can threaten Darmanitan with Scald or stall it out with Recover. Gyarados is capable of avoiding the 2HKO from a sun-boosted Flare Blitz, even with Stealth Rock, but its lack of reliable recovery means that it won't be able to consistently check Darmanitan in the sun. Faster users of Choice Scarf, such as Terrakion, Keldeo, Salamence, and Latios, can all outspeed it and threaten it in some way.
The Life Orb set, on the other hand, is quite easy to check. Because most Life Orb Darmanitan sit at a below-average 289 Speed, there are quite a few offensive threats that can outspeed it, including Starmie, Terrakion, Latios, Latias, Hydreigon, and Salamence. With that in mind, Life Orb Darmanitan under the sun is pretty much impossible to counter. One of the few things that can survive a Flare Blitz twice and live to tell the tale is Politoed, as it instantly summons rain upon entry. Even then, there's still a chance of it being 2HKOed. Still, defensive Politoed is generally the best counter to all of Darmanitan's sets.