Houndoom

Flash Fire
Grants immunity to Fire and increases Fire's power 50% when hit by a Fire move.
Early Bird
Reduces sleep time by 50%.
Type Tier
Dark / Fire BL
Statistics
Min- Min Max Max+
HP
75
- 291 354 -
Atk
90
194 216 279 306
Def
50
122 136 199 218
SpA
110
230 256 319 350
SpD
80
176 196 259 284
Spe
95
203 226 289 317
Name Item Nature

Special Sweeper

Leftovers / Lum Berry Timid
Moveset EVs
~ Flamethrower / Fire Blast
~ Pursuit / Crunch
~ Hidden Power Grass / Hidden Power Ice / Crunch
~ Will-O-Wisp / Beat Up
68 HP / 252 SpA / 188 Spe

This is the standard set for Houndoom. You can afford to mix and match all moves easily, as each has its own use. Pursuit is one of the main reasons to use Houndoom, though: it always kills off Gengar if it switches out, allowing things like a Snorlax without Shadow Ball to dominate. Beat Up should only be used on Blissey—it should 2HKO her as long as your team is alive and not statused. This is why Lum Berry is a good option: you can take a Blissey Thunder Wave with Houndoom once without being screwed.

Crunch is useful for OHKOing Gengar if it wants to stay in as well bringing some generally good STAB power to the table. Hidden Power Grass is for Swampert and Tyranitar mostly, it should 2HKO both of them. Will-O-Wisp already hurts them considerably though, and also hinders Snorlax, Salamence and Gyarados among others. You may not want to Will-O-Wisp a Milotic. Hidden Power Ice hits Salamence and Flygon, but Will-O-Wisp completely shuts them down, as well.

Name Item Nature

Reversal

Salac Berry Lonely
Moveset EVs
~ Substitute / Endure
~ Reversal
~ Flamethrower
~ Howl / Crunch
252 Atk / 80 SpA / 176 Spe

While this can be a pretty nasty surprise for Snorlax and Blissey, Blaziken fills this role so much better with STAB, Blaze, and more Attack. Flamethrower Steels that Reversal cannot kill, while using either STAB Crunch to kill Ghosts, or boosting your Attack a little with Howl. You probably won't want Shadow Ball, despite the higher Attack investment, as Houndoom's high base Special Attack and STAB make it do more to Ghosts with Crunch, unless you can get in a few Howls (which is rarely going to be the case).

Name Item Nature

Counter

Leftovers / Salac Berry Timid
Moveset EVs
~ Will-O-Wisp
~ Counter
~ Flamethrower
~ Protect / Pursuit
68 HP / 252 SpA / 188 Spe

Counter can be a load of fun on Houndoom. After Will-O-Wisping a Tyranitar, you will always survive an unboosted Rock Slide (though barely), so you can bounce it back for the OHKO. Snorlax can be messed up by it, and there's a small chance you survive a Will-O-Wisped Choice Banded Aerodactyl Rock Slide as well. To guarantee that, use 52 HP and 48 Defense EVs. The last slot is really just filler, you can put about any move there. Protect can scout which move your opponent is going to use, which can be handy against Swampert, who might use Surf or Hydro Pump instead of Earthquake.

Name Item Nature

Sunnybeam

Leftovers / Salac Berry Timid
Moveset EVs
~ Sunny Day
~ Solarbeam
~ Flamethrower
~ Toxic / Crunch / Endure
68 HP / 252 SpA / 188 Spe

Houndoom isn't that good at Sunnybeaming since it doesn't outspeed everything, but it can cause some havoc in late-game and give some shock value when your opponent switches in Swampert. Sunny Day turns Solarbeam into a one-turn move, powers up Flamethrower and makes Water moves less powerful, all of which benefit Houndoom. You don't want Tyranitar to switch into a Solarbeam though, as it will have to charge up first and you'll be forced to stay in while Tyranitar OHKOs you with Rock Slide or switches out again to a counter, so if you predict Tyranitar, use Sunny Day again.

Other Options

As mentioned before, Houndoom has a load of useful moves that it can put on nearly all sets and use effectively. First off, Fire Blast is equally as great as Flamethrower anywhere on any set. It averages more damage per turn, but Houndoom cannot afford to miss with its low defenses, so it's still a gamble. Houndoom can combine Early Bird and Rest for a one-turn full recovery, but since Houndoom is so weak defensively this is not the best option. Sleep Talk, however, is pretty useful as you can sop up sleep moves easily and surprise the hell out of things like Venusaur and Jynx with a Sleep Talked Fire move. Toxic is great on any set as it ruins the stalling potential of the Waters and makes Gyarados, Salamence and Tyranitar a tad useless as well.

EVs

In most Houndoom sets, you'll want at least 300 Speed with Timid (188 EVs), or just max Speed with Modest or Timid. Special Attack should nearly always be maxed, and anything you have left can go in HP. Reversal or generally physical sets need to max Attack instead. The Counter one needs some defenses to survive specific things (like Aerodactyl). The EVs listed on every set are good enough to start with.

Opinion

Houndoom is high risk / high return. On one hand, it is a great asset to teams as a threatening Special attacker that can instantly remove Gengar and Alakazam from the field with Pursuit and 2HKO the most popular Special sponge with Beat Up. On the other hand, it is really fragile and not quite as fast as you might want him to be: it is slower than Gengar, Alakazam, Raikou and Salamence by sheer base stats. However, altogether it is a usable borderline Pokémon with good potential.

Counters

Dugtrio outspeeds and OHKOs Houndoom every time with Earthquake. Dugtrio cannot be brought in easily though, due to the risk of Will-O-Wisp. Modest Houndoom can also OHKO with Flamethrower or Hidden Power. Salamence, Gyarados, Flygon, and Tyranitar resist Fire attacks, can take a Crunch or two, and will usually OHKO Houndoom with Rock Slide or Earthquake. They are vulnerable to Will-O-Wisp however. Suicune, Swampert and Milotic, also known as "the bulky Waters", wall Houndoom easily. Milotic can even absorb Will-O-Wisp to trigger Marvel Scale. Swampert can easily be screwed over by Will-O-Wisp or Hidden Power Grass, though. About any Water-type will be very annoying to Houndoom to get past, though some are more easily taken care of than others. Poliwrath can be a real annoyance with its Dark resistance and STAB Fighting moves. Aerodactyl can outspeed Houndoom and OHKO with Rock Slide and Earthquake. Despite Aerodactyl's resistance to Fire, it cannot switch in reliably because of Will-O-Wisp and low Special Defense.