Oh, Flareon… I am so, so sorry.
The sad thing about Flareon is that she’s so like Vaporeon and Jolteon in so many ways. Her stats, of course, are just as good. She has an analogous ability, Flash Fire (rather than converting Fire attacks to health, as Volt Absorb and Water Absorb do, it converts them into extra power for her own Fire attacks, but the practical strategic implications are similar). She has many of the same supports moves, like Baton Pass and Wish. Somehow, though, it all just completely fails to come together.
Well, no, not somehow. I know exactly why, and it’s incredibly boneheaded.
Let’s back up a bit. Way back in Red and Blue, when Flareon was first introduced, Fire-types got shafted pretty badly: there were no Steel-types around for them to bully, very few of them had any attacks types outside of Fire and Normal, and the importance of powerful Rock Pokémon like Golem and Rhydon ensured that most teams had a very simple, no-nonsense way of saying “no” to them. I mention this so that, when I say that Flareon looks back on Red and Blue as her glory days, you will understand exactly how grim things have been for her since then. Back then, most Fire Pokémon relied on a moveset something like [Flamethrower/Fire Blast – Body Slam – Hyper Beam – XXX], where XXX is whatever rubbishy little support move that Pokémon happens to favour (maybe Reflect or something in Flareon’s case), and Flareon was actually very good at this moveset, thanks to her obscene attack stat and excellent special stat. She was worryingly slow, but packed more power than any other Fire Pokémon with the exception of Moltres, which was something of a niche. Sure, it was a crappy niche that made her a sitting duck against Golem, Rhydon, Onix, Kabutops, Omastar, and goodness knows what else, but it was hers nonetheless. Then Gold and Silver split special into special attack and special defence. Vaporeon and Jolteon suffered hits to their special defence, which hurt Vaporeon, but not terribly. Flareon took the loss to her special attack instead. Her Fire attacks were still quite potent, but were no longer the force they had once been. On the other hand, she expanded her physical movepool with the addition of Shadow Ball and Iron Tail. You win some, you lose some. Curse is also an option from here on out, if you want to try turning Flareon into a physical tank, but I’m not convinced she’s really tough enough for that. After that… well, honestly, after that Game Freak seem to have forgotten about Flareon. She was mediocre, and mediocre she stayed. Like all Fire Pokémon, she enjoyed the introduction of Overheat in Ruby and Sapphire, but did so while sighing wistfully at the memory of her long-lost special stat.

Diamond and Pearl, by all rights, should have revitalised Flareon, as they did so many other Pokémon whose stats and movepools were so sadly mismatched. With physical Fire attacks on the scene at last, Flareon should finally have regained much of her former power… but she didn’t. While Rapidash, Charizard and Arcanine paraded around showing off their shiny new Flare Blitz attack, Flareon sat in the corner with Fire Fang, wondering what she had done to deserve this. Platinum gave her Superpower, which helped, and Lava Plume, which just rubbed salt in the wound, but Game Freak have never yet seen fit to let Flareon have a physical Fire attack that doesn’t suck. Arguably, it might not help even if they did – Flareon’s offensive movepool suffers from the same narrowness that characterises her brothers and sisters, but with her weaker special attack, she can’t even rely on Shadow Ball as Jolteon can. Superpower is great, and Fire and Fighting go well together, but it can only do so much, it makes Flareon’s physical stats weaker after she uses it, and it’s really all she’s got. Jolteon and Vaporeon work around their restrictive movepools by adopting support roles, but Flareon is too fragile for Wish and too slow for Baton Pass – she has the weaknesses of both, and the strengths of neither. Her stats seem to mark her out for some sort of Machamp- or Ursaring-like all-offensive approach, but she has nothing to attack with. I… guess you could use Flareon as a special tank, since she does still have excellent special defence and good special attack, but it’s not like she’s good at that either; she doesn’t have a lot of hit points and her special movepool is even more limited than Jolteon’s (she doesn’t even get Signal Beam, for goodness’ sake). Even her Dream World ability taunts her; Guts, which boosts a Pokémon’s attack in response to poison, paralysis, and so on, is an awesome ability for a physical attacker to have, but Flareon doesn’t actually learn any damned physical attacks. In short, Flareon is terrible. She really doesn’t deserve to be terrible, and there’s no real reason she should be terrible, but she is, and she will likely remain so until the end of time because, let’s face it, if Game Freak had any intention of fixing her, they would have done it by now.
Right; now that that unpleasantness is out of the way…
Flareon is a Fire Pokémon, and because she is a Fire Pokémon, the Pokédex feels a pressing need to explain to us, repeatedly and insistently, just how hot she is (just a hair under 900 degrees Celsius, her resting body temperature is hot enough to vaporise sulphur). Her fluffy fur, apparently, is supposed to radiate heat to help regulate her body temperature, which… is not really how fur works; animals lose the most heat from regions that get a lot of blood flow, and fur doesn’t have blood in it, but I suppose we can guess that her hairs have some kind of dense heat-conducting core or something. In terms of physical appearance, she’s the most like Eevee, and retains a similar aesthetic angle, aiming to be simply adorable where Vaporeon tries to achieve more of an untouchable beauty. In fact, apart from her fiery colour scheme, Flareon barely changes at all from Eevee! It’s not a bad thing, per se, that Flareon shares aesthetic goals with her juvenile form, and of Eevee’s seven evolutions, one of them had to be the one who was least altered. It’s just something of a shame that it happened to be the perfectly generic Fire-type whose main distinguishing feature is just a little bit nonsensical, and even more of a shame that it happened to be the one who’s so very severely handicapped in battle. I don’t dislike Flareon, and she fills an important place on the spectrum of Eevee’s evolved forms – two, actually, with both cuteness and firepower – but she’s one of those Pokémon that, in my opinion, have never been given the kind of attention they should have had.

Since it seems to be a theme I’ve talked myself into discussing, I should really look at Flareon’s environment. What kind of ecosystem is she adapted for? Well, first of all, we know that radiating body heat is a concern for her; that suggests that, contrary to the stereotype that Fire-types like to live in hot places, Flareon actually prefers a temperate climate. A wet environment would cause problems for her since she relies on fire, but at the same time she probably wouldn’t live in a very dry place either; she’d risk causing perpetual wildfires. We’re probably looking at somewhere with moderate temperature and humidity, then – somewhere like temperate grassland. I imagine Flareon lying down for a nap in whatever shade she can find during the hottest part of the day, the way lions do, and letting her internal fire slowly burn down, burning just hot enough to keep going. She hunts in the mornings and evenings, loosing sheets of fire to scorch patches of grass and flush out prey. Flareon’s hunting practices actually serve an important ecological purpose too; by regularly engaging in controlled burning of small areas, she constructs natural firebreaks that prevent uncontrolled fires from getting out of hand. Flareon’s own flames are so hot that they reduce the grass to ashes in moments, burning themselves out and exhausting all the available oxygen before they can spread. That’s my story and I’m sticking to it. In summary, then, Vaporeon is a coastal or aquatic Eevee, Jolteon is a desert Eevee, and Flareon is a grassland or savannah Eevee. More on what all this means later.
I don’t want to be too harsh on Flareon, because she’s likeable enough, but I honestly think they did her wrong. She’s far from irredeemable; you could fix her mechanical problems by just, y’know, giving her attacks that don’t suck, and you could fix her flavour problems just by coming up with some way for her to be different from every other Fire Pokémon with a core temperature of 900 degrees. Her art is fine; she’s maybe not as interesting as Vaporeon and Jolteon, but she still has, and achieves, clear aesthetic goals that distinguish her from the other two, so it’s not all bad news. The good news for me is that Flareon is something of a low point – she has some of the trickiest problems of the family. Not to say that her newer brothers and sisters don’t have their problems too… but we’ll burn that bridge when we come to it.