Weavile certainly isn't winning any awards defensively, as not only is he stripped of 25% of his health every time he switches into Stealth Rock, but he also has poor defensive stats and weaknesses to common attacking types, namely Rock, Fire, Steel, and Fighting. He can also be easily walled, so outside of the late-game, his sweeping potential is limited. On the other hand, Weavile's combination of Speed, Attack, and useful STAB moves can be a great asset to many teams. Is Starmie causing you trouble? Pursuit it to death. Is Choice Scarf Flygon irritating with its high Speed? Not with Weavile's Ice Shard in the wings. While Weavile faces stiff competition for STAB Dark-type attacks from Tyranitar, Weavile has significantly higher Speed and access to Ice Shard which can sometimes give him the edge depending on what your team needs. Overall, Weavile can be extremely threatening with proper team support, and as such, he is a physical attacker who should not be underestimated.
At first glance, this Weavile seems to be a generic physical attacker, but he functions as insurance against many of the metagame's top threats. This is mostly thanks to Weavile's STAB Pursuit, which allows him to outspeed and KO threats such as Gengar. Starmie is also OHKOed by Pursuit on the switch, letting your Gyarados or Infernape sweep with their check eliminated.
Weavile's STAB Ice-type attacks allow him to easily OHKO any Dragon-type Pokemon in OU bar Kingdra. Ice Shard is used on this set as it handles both Choice Scarf Flygon and Dragon Dance Dragonite regardless of their Speed. Low Kick OHKOes Tyranitar, whom Weavile can outspeed even after a Dragon Dance, and hits Steel- and Normal-types for super effective damage as well. Ice Punch can be used in the last slot as a means of hitting Flying- and Grass-types harder, while Night Slash can be used for stronger Dark STAB. Choice Band is the main item choice for extra power, but Life Orb is a viable option if you wish to retain decent power and still have the freedom to switch attacks.Team Options & Additional Comments >>>
Weavile's combination of Speed and power makes him an excellent candidate for a late-game sweeper when his counters are weakened or gone altogether. With Swords Dance to boost his already impressive Attack, very few Pokemon can switch in on his boosted Night Slash, and your opponent will usually have to resort to a priority move or a Choice Scarf user to take down Weavile without taking significant damage themselves.
Night Slash is a great STAB move that hits most types neutrally, and Low Kick lets Weavile handle Steel-types and Tyranitar. Ice Shard is generally a better option than Ice Punch because it OHKOes the same Pokemon, such as Flygon, who you would be hitting with Ice Punch, but allows Weavile to always strike first. It is also helpful against faster Pokemon, particularly Jolteon, who is always OHKOed by a +2 Ice Shard after taking Stealth Rock damage. Still, Ice Punch is an option if you want a more powerful attack to use, especially against bulky Ground-types, namely Hippowdon.Team Options & Additional Comments >>>
Weavile is one of the few Pokemon who can stop the popular suicide leads in today's metagame, particularly Azelf and Aerodactyl. Fake Out is the most important move on the set, as it allows Weavile to break the Focus Sashes on leads such as Aerodactyl, Infernape, and Azelf, while keeping his own intact. Night Slash lets Weavile finish off Azelf, while Ice Punch handles Aerodactyl.
The other half of the set, Taunt and Counter, allows Weavile to deal with slower, bulkier Pokemon such as Bronzong. First, Taunt to prevent them from using a support move such as Stealth Rock. Now that they are forced to attack, Counter back their physical attacks for an OHKO. This strategy also works when facing a lead Metagross, who will probably attack from the start, so using Counter first is advised. This strategy is very risky, especially when facing dangerous leads such as Infernape, but if you predict correctly, the payoff is enormous.Team Options & Additional Comments >>>
Punishment is useful for taking out Calm Mind users such as Jirachi, as it will do more damage than Night Slash after a few boosts. Assurance can also be used if you have Stealth Rock support, but Night Slash is generally the better choice due to its greater Base Power, high critical hit rate, and general reliability. Stay away from using special attacks, because although Weavile gets Nasty Plot, he will never be doing much damage with his terrible Special Attack stat. Focus Punch and Substitute can be used if you want Weavile to pack a more powerful Fighting-type move, although Life Orb and Substitute, as well as entry hazards, will deteriorate Weavile's health quickly. Reflect can be used, but it has little utility on such a defensively challenged Pokemon.
Always use a Speed-boosting nature to take advantage of Weavile's great Speed stat. Maximizing Speed isn't needed, so just aim for 373 Speed (216 EVs) to outrun Base 120 Speed Pokemon such as Dugtrio and Alakazam, and put the remaining EVs in HP. Max Attack is a given, because Weavile needs all the power he can get. On the lead set, you needn't put any EVs into HP, because the aim is to activate Focus Sash quickly so that Weavile can then use Counter to OHKO the opposing lead.
Checks and Counters
Steel-types are particularly troublesome for Weavile. Scizor is easily Weavile's greatest enemy; he can KO Weavile with either Bullet Punch or U-Turn while taking minimal damage from any of Weavile's attacks. Similarly, Metagross does a fine job beating Weavile with either Meteor Mash or Bullet Punch, although he must be wary of switching into a Choice Band Night Slash. Jirachi is a good option as he is able to withstand any attack Weavile uses and respond with Iron Head. Bronzong is also a good counter to Weavile as Weavile will have a hard time breaking through his high defenses. He can use his defensive ability to set up Stealth Rock and then subsequently KO Weavile with Gyro Ball. Skarmory can come in on Weavile to set up Spikes and then Roost off any damage Weavile inflicts, or can opt to KO Weavile with Brave Bird. Forretress can also switch into Weavile with impunity and proceed to either set up hazards or KO with Gyro Ball.
Pokemon with a high amount of bulk are also a challenge for Weavile, as with Weavile's pitiful defenses, almost any attack will put him in a dire situation. Gyarados is a good example, as with Intimidate he is able to take any attack Weavile throws at him and KO Weavile with Waterfall. Swampert can switch into Weavile and KO him with Earthquake, with Weavile failing to do any meaningful damage. Suicune and Vaporean can do much of the same, being able to KO Weavile with Surf before Weavile can KO them.
Machamp is an excellent counter to Weavile, as Weavile isn't able to do nearly enough damage to KO him before he responds with a super-effective DynamicPunch. Faster Pokemon are also major threats to Weavile. Choice Scarf Heatran and Lucario can switch into everything barring Low Kick and then proceed to outspeed and KO Weavile with their respective STABs. Jolteon outruns Weavile and can proceed to deal heavy damage with Thunderbolt. Infernape and Hitmontop can switch into any of Weavile's moves and KO him with priority Mach Punch.