Using multiple Fire Pokemon is helpful because it puts immense pressure on the opponent and requires no set up unlike the other forms of HO because it has such insane power from the get go.
Flint of the Sinnoh Elite Four said:
You have to go with Fire-type Pokémon. It's the way of the future!"
...which is not likely unless something big happens like GameFreak releasing Drought Victini for UU players to use or something and yet even in this piece of programmed speech by mere AI there has to be some inkling of truth.
Please let me explain to you why I believe Fire is the best offensive type in UU and why you should use some of them on your team.
Statistics tell us so much and I don't mean August statistics because one of the only things we are capable of is ranting about how Ambipom sucks apparently. I mean the statistics that make up a Pokemon - their typing, move pool, ability and base stats which as you know is what essentially composes a Pokemon. There are six fire types in our tier, Darmanitan, Victini, Arcanine, Chandelure, Houndoom and Rotom-H. I will not be talking about Rotom-H because its so different from most of Fire types from its lack of Flare Blitz/Fire Blast which I consider essential to a Fire Pokemon's success. I will also leave out much about Chandelure individually as the posters before me have already given good accurate information on it and its already agreed upon to be top tiered and much about Houndoom individually because I am unfamiliar with it, both facing it rarely and using it even more rarely.
Darmanitan
I will speak chiefly about Darmanitan and Vicitni as I have had great amounts of experience with them on the ladder. Statistically Darmanitan has the greatest attack power out of any UU Pokemon while retaining enough speed to outpace the common base 85 speed tier and enough bulk to use FlareBlitz multiple times after Stealth Rock without instantly dying. This alone makes it one of UU's top Pokemon. Power wise with Life Orb Darmanitan is essentially unrivalved except by Choice Band Victini which I will speak to shortly, and if it so chooses to run a Choice Scarf no Pokemon will have its combination of speed and power before set up. Its move pool is not wide but contains everything it needs, including the essential Flare Blitz and U-turn and coverage moves to hit Rock and Fire Pokemon. Fire is resisted by Rock and Water and Fire. Water is perhaps the most problematic because it takes up much of the tier, but realize that most Water do not have reliable recovey and cannot stand up to repeated assaults; Darmanitan can bypass counters with U-Turn. Darmanitan has only two problems a Stealth Rock weakness and being slower than some key threats like Flygon, which it can incidentally OHKO with an Adamant Life Orb after Stealth Rocks. Sheer Force is is crazy with Flare Blitz and Darmanitan making it almost unwallable except by Suicune and Slowbro
Victini
This is not only the bulkiest of the Fire five but also the strongest (I discount Choice Band Darmanitan because I find Life Orb to be superior on Darmanitan) and the fastest so something must be right here. Indeed almost everything is, with a Choice Band equipped Victini's damage output can far out muscle say Choice Band Dragonite doing enough damage to 2HKO the likes of physically defensive Milotic and offensive Swampert with just Stealth Rock - with the resisted V-Create. Don't try not getting blasted in two/one hit unless you have good defenses and a resist. Amazingly Victini is not lacking in Speed either being able to outpace fairly fast walls like Gligar after a speed drop which is cool and being able to outpace the majority of the offensive Pokemon before a drop. Victini more than any of the other Fire Pokemon helps set up late game win conditions because V-Create is easy to spam with perfect accuracy (after Victory Star) and a drawback easily offset by Choice Scarf. Victory Star makes V-Create never miss and Zen headbutt only miss one percent of the time which is fairly insignificant. Victini's movepool includes Fusion Bolt and many special moves like Thunder and Grass Knot to break through certain counters so it is not lacking at all.
Arcanine
This is the only Fire Pokemon that can competently use a defensive set but I will not talk about that since I want to speak to offensive Fire now. His power is very good but low compared to the other more terrifying Fire Pokemon so he poses a threat to offensive Pokemon but not often very bulky Pokemon. Flygon for instance is KO's by Flare Blitz and Extremespeed all the time and Arcanine still poses good defenses with Intimidate. This is what allows Arcanine to have a huge amount of switch ins compared to his fellow Fire Pokemon, being able to switch into Victini or Scrafty is useful. Move pool wise Arcanine has always been fairly shallow until this generation where he has a good six choices on offensive sets - Close Combat, Extremespeed, Morning Sun, Wild Charge, Crunch and of course Flare Blitz. Howl is mediocre as its hard counters will still beat it. Nothing will be spared either neutral STAB or Super Effective coverage move except Swampert which loses to three Close Combats. Arcanine is the least versatile though as it will almost always use a Life Orb attacking set.
Fire
Out of the statistics making a Pokemon I have not yet touched upon the type itself, Fire, which is undoubtedly one of the most offensive in UU if not the most offensive. They get the best attacking STAB moves, Flare Blitz and Fire Blast (and V-Create) which are all the strongest power moves in UU backed up by STAB and the strongest attack stats in UU. Because the Pokemon that resist them are hit by super effective coverage moves they will always lose if they try to counter multiple Fire Pokemon without recovery. For instance if Rhyperior has to switch into Arcanine's Flare Blitz and then eat a Close Combat, it will KO Arcanine but lose to the next Fire opening a line of attack by say a Victini. Houndoom can irreparably maul Fire resists with its secondary STAB Dark Pulse after luring them in and smacking them after a Nasty Plot or it can outright beat them one on one with Passho Berry.This can only be partially alleviated by running multiple Fire counters because the user loading up on Fire Pokemon will certainly have an answer to them - say a Roserade which can Spike down to further increase pressure. Chandelure despite attacking specially shares many of their checks and counters because they use the same STAB - Fire of course - which means bulky waters and Snorlax can often counter one but certainly not two or three or even four Fire Pokemon on the same team. Fire has its weakness but it does not need to let your opponent capitalize on them if it can just run a single defender to absorb moves and something else to use Rapid Spin for them. In any case teams that use multiple Fire Pokemon, I have seen a few of them on the ladder, must employ a fast lead to prevent Stealth Rocks or there will usually be too much pressure on the attacking Fire team to kill. By this I mean Darmanitan can no longer throw around U-Turns for fun or Victini can no longer count on its good bulk to check threats without risking huge residual damage. Fire Pokemon need little support, but if you do not have Houndoom or Chandelure you need a way to deal with Slowbro as well as defensive Arcanine and regardless you need a way to deal with Suicune. Those three threats are the only ones capable of taking repeated beatings from Fire Pokemon. It is very important to play logically, never lock yourself in for example a V-Create while your opponent has a Kingdra waiting to Rain Dance sweep you. Do not let Extremespeed Arcanine die if your opponent has a Sharpedo. Keeping this in mind will help keep your chances of winning high.
