You're (not) gonna hear me roar!
<li>Pyroar possesses high Special Attack and Speed stats.</li>
<li>It has a unique typing, which gives it an immunity to Ghost.</li>
<li>Pyroar's STAB Hyper Voice lets it hit targets even behind Substitute.</li>
<li>Pyroar's typing gives it an additional weakness to omnipresent Fighting-type attacks.</li>
<li>It has poor defensive typing and defenses, meaning Pyroar can be easily revenge killed by almost any attacker.</li>
<li>On top of its Stealth Rock weakness, Pyroar is vulnerable to every other entry hazard.</li>
<li>It has near-useless abilities, as none help Pyroar sweep on its stronger special side.</li>
<li>Pyroar's pitiful Attack stat prevents the potential for mixed attacking sets.</li>
<li>It has a limited movepool.</li>
<li>Pyroar is mostly outclassed by almost every other Fire-type, such as Charizard, Arcanine, and Houndoom.</li>
<p>name: Special Attacker<br />
move 1: Fire Blast<br />
move 2: Hyper Voice<br />
move 3: Hidden Power Fighting<br />
move 4: Taunt / Will-O-Wisp<br />
ability: Unnerve<br />
item: Life Orb<br />
evs: 4 Def / 252 SpA / 252 Spe<br />
<p>This is the only viable set that Pyroar can currently run. Fire Blast and Hyper Voice provide great STAB coverage, only being resisted by Rock-types. Furthermore, Hyper Voice is now capable of hitting past Substitute, giving Pyroar a viable revenge killing niche. Hidden Power Fighting rounds off the coverage in order to land super effective hits against the likes of Tyranitar and Barbaracle. Due to a limited offensive movepool, Taunt and Will-O-Wisp take up the last slot. Taunt is useful to prevent status effects, recovery from special walls, and entry hazards from being used, whereas Will-O-Wisp is nice to cripple typical Pyroar switch-ins, such as Tyranitar and Azumarill.</p>
<p>Unnerve is the safer ability choice, as if Rivalry was to be used and Pyroar is against Pomemon of opposite gender, its damage is greatly reduced. Life Orb is required so Pyroar can dish out as much damage as possible, as it has no other reliable means of increasing its damage output. Rapid Spin support is recommended, as Pyroar will otherwise go down rather quickly from entry hazard damage and Life Orb recoil. Starmie is a good choice, resisting Pyroar's Fighting- and Water-type weaknesses. Using Pokemon to take out bulky Water- and Rock-types and special walls work nicely as well. Mega Lucario fits the bill perfectly, decimating nearly all such Pokemon with its monstrous Attack stat and STAB Close Combat, which can be further powered by Swords Dance.</p>
[Checks and Counters]
<p>There are multiple ways to defeat Pyroar. Simply spilling out entry hazards, such as Stealth Rock, Toxic Spikes, and Sticky Web, significantly impedes its sweeping ability. In terms of outright walling Pyroar, Chandelure comes to mind, as between its Ghost typing and Flash Fire ability, Pyroar can't scratch it. Special walls and tanks, including Blissey, Florges, Togekiss, Tentacruel, and Goodra, instantly shut Pyroar down and can cripple or KO it back. Bulky Rock- and Water-types, despite Pyroar running Hidden Power Fighting for the former, work well. Tyranitar, Barbaracle, Vaporeon, and Rotom-W are examples of such. Due to Pyroar's lack of defenses, it can also be easily revenge killed by faster threats such as Greninja, Talonflame, Alakazakam, Starmie, and Gengar. Lastly, priority users in Mach Punch Breloom, Aqua Jet Azumarill, and Extreme Speed Lucario can easily take Pyroar out.</p>
I was thinking about a Moxie mixed sweeper with Work Up, but there literally is nothing that Pyroar could adequately take advantage of to make this a viable set. Work Up/Fire Blast/Return/Hidden Power Fighting|Bulldoze is pretty much the only good set to be running, but even then, Pyroar's atrocious Attack stat leaves much to be desired and its terrible defensive typing and defenses won't even allow it to set up to begin with.
A Sunny Day set with Solarbeam seemed intriguing as well, as Solarbeam covers the Rock- and Water-types that like to switch in on Pyroar; however, the same flaw with Work Up applies here too. Pyroar just can't set Sunny Day up, and with the advent of Tyranitar and opposing weather effects, it's not worth it.
Pyroar also learns Dark Pulse, but I find it to be a redundant move to be run as it doesn't particularly help with anything. Most Psychic-types are either faster than you or are frail enough for Hyper Voice to deal significant damage (OHKOes Starmie with entry hazards). Gengar and other Ghost-types are roasted by Fire Blast. It serves no purpose as far as I know.