Heatran has a unique niche in Ubers due to its very valuable resistance to the extremely powerful and common Dragon-type attacks, as well as a unique set of other resistances backed by respectable bulk. In addition to absorbing Dragon-type attacks, Heatran can successfully roast other Steel-type Pokemon such as Forretress and Ferrothorn, who can otherwise be troublesome. With a Speed stat just good enough to outpace stall-based Pokemon and access to great moves such as Taunt, Roar, and Toxic—as well as the ability to scare away the aforementioned defensive Steel-types—Heatran is incredibly useful in Ubers as a stallbreaker. Although Heatran's Special Attack stat is nothing to scoff at, it is outclassed offensively by other Pokemon such as Reshiram and Ho-Oh. A STAB Fire-type attack will still pack a punch in the sun, though. Heatran is definitely worth using and can be a major threat to stall teams when played correctly.
Because of serious offensive competition from the likes of Reshiram, this set does what Heatran is best suited to in Ubers: stallbreaking. Because of its great bulk, typing, and movepool, Heatran can easily put a stop to defensive Pokemon and their stall-based shenanigans. Taunt is the crux of the set, stopping all Pokemon from recovering lost health, using status moves, and setting up entry hazards. Notable examples are Blissey and Chansey with Wish or Softboiled, and Giratina with Rest. Although the common Steel-type Spikes users—Forretress and Ferrothorn—will usually switch out due to a type disadvantage, either of them can take Fire-type attacks from Heatran when its raining, making Taunt advisable in that situation. Heatran cannot prevent entry hazards from being set up all of the time, because it is likely that Ferrothorn or Forretress will have an opportunity to switch in on a different team member. Double switching is vital against those Pokemon, preventing entry hazards from being set up on your side, and increasing your own entry hazard damage, provided they are in play.
Toxic is great on Heatran and deals increasing damage to opponents. Whereas it is useless against most stall-oriented Pokemon—Steel-types such as Ferrothorn and Forretress being immune and Blissey having Natural Cure—it can, however, be useful for poisoning common switch-ins to Heatran such as Palkia, Giratina, Kyogre, and Lugia. Ferrothorn can easily switch in on Palkia, setting up entry hazards while Palkia's health slowly withers away. In the case of Giratina, Heatran can use Taunt, preventing it from healing itself with Rest, and resists most of its attacks apart from a rare Earthquake. Kyogre spells trouble for Heatran, so poisoning and switching to something that walls Kyogre is the best that Heatran can do. Roar can shuffle the opponent's team, and is useful when the opponent switches. Roar also stacks entry hazard damage, and can take chunks of HP from Pokemon weak to Rock-type attacks, such as Reshiram, Ho-Oh, and Rayquaza. Pokemon that might attempt to set up on Heatran, such as Rayquaza, are in for a surprise, as they can be easily phazed out.
Flamethrower rounds off the set, and is Heatran's only attacking move. It is used over Fire Blast, as the perfect accuracy and extra PP are appreciated on less offensive sets. Flamethrower can toast Steel-type Pokemon, and do decent damage to others, especially under the sun, 3HKOing Blissey and Giratina and 2HKOing Lugia, assuming Stealth Rock is in play. Lava Plume is an alternative to Flamethrower, sacrificing the extra damage for a larger burn chance, which can be useful for halving a Pokemon's Attack stat and inflicting passive damage every turn. Protect is also an option to stack Leftovers recovery, as well as scout a Choice-locked Pokemon's attacks.Team Options & Additional Comments >>>
Heatran can act as a potent revenge killer with a Choice Scarf and sun support, capable of revenge killing Darkrai, Mewtwo, and weakened Arceus. Its Steel typing is a huge asset over Choice Scarf Reshiram, granting Heatran an invaluable resistance to ExtremeSpeed, immunity to Toxic, and a neutrality to Stealth Rock. Overheat is Heatran's STAB move of choice, OHKOing Darkrai and Mewtwo in sunlight and dealing a massive amount of damage to Arceus. Hidden Power Rock, alongside Heatran's typing and Flash Fire ability, allows Heatran to check Ho-Oh, who is otherwise a serious threat to sun teams. However, Hidden Power Ice is also an option for its ability to OHKO Rayquaza. Dragon Pulse hits Palkia, Giratina-O, and Giratina for moderate damage, the latter two being unable to do much in return. Flamethrower provides a reliable STAB move for late-game sweeping, whereas Fire Blast obtains notable 2HKOs in the sun where Flamethrower cannot; more specifically Bulk Up Dialga and Arceus. Earth Power is also usable as it deals with other Heatran easily, and is Heatran's strongest option against Dialga in the rain. Heatran is an excellent check for Dialga in general, as few carry Aura Sphere and fewer still carry Earth Power.Team Options & Additional Comments >>>
Heatran is far less versatile in the Ubers environment, but other options are available. A Choice Specs set can be run, but Reshiram packs much more offensive power. The only reason to use Heatran instead of Reshiram is Heatran's typing, which gives it resistance to Dragon-type attacks and neutrality to Stealth Rock. A Life Orb can be used instead of Leftovers to pack an extra punch, but this is not recommended on a set with only one attack. Fire Blast can be used instead of Flamethrower or Lava Plume for a sizable power increase should you want to take down your enemies a little faster. Dragon Pulse is a very usable option, allowing Heatran to nail common Dragon-types that switch in, such as Palkia and Giratina. It can also be used to allow Heatran to pick off a Dragon-type such as Rayquaza locked into Outrage.
Checks and Counters
Anything that can exploit Heatran's gaping 4x Ground-type weakness makes a decent check to it. Pokemon such as Garchomp, Ho-Oh, and Groudon with a few Speed EVs can outspeed and OHKO Heatran with Earthquake. Giratina-O can also OHKO Heatran with Earthquake, even though it is a rare move to be seen on the legendary dragon. However, these Pokemon aren't a major problem for Heatran, as it can simply switch out of danger. Kyogre can counter Heatran absolutely, as it takes pathetic damage from Flamethrower, and—in the case of RestTalk variants—does not mind being poisoned. Kyogre also summons rain, which halves the power of Flamethrower. While rain is in play, Pokemon such as Manaphy and Palkia can OHKO Heatran with ease.
Heatran's Dream World ability is Flame Body. This might be useful on some defensive sets in order to buff up Heatran's defense. In addition, Flame Body prevents the rare, but incredibly annoying, Trace Gardevoir and Porygon2 from setting up on it. However, Flash Fire is usually the better option, otherwise, it would be taking neutral damage from Fire-type attacks. The more resistances, the better.