Moves
Boomburst is Kyurem-W's main STAB move and quite easily spammable with few repercussions. Boosted by Refrigerate, Choice Specs, and STAB, it is immensely powerful and cuts through many of the metagame's tanks and walls alike, including Giratina, Zygarde-C, Primal Groudon, Dialga, Ho-Oh, and Mega Tyranitar. The second slot is typically used for coverage, specifically to hit Steel-types. Earth Power is most reliable, as common Steel-types that resist it such as Ferrothorn and Celesteela fall to Boomburst. Blue Flare can also be used, as it combines power with coverage against every non-Flash Fire Steel-type. Alternatively, Magma Storm is an option that trades reliability for the ability to beat Shedinja and RegenVest Steel-types thanks to its trapping and residual damage. Secret Sword is another option, as despite having the lowest Base Power of the three, it is the most reliable, hitting every common Steel-type bar Aegislash. It also hits Mega Gyarados and inflicts physical damage, complementing Kyurem-W's special power well by hitting RegenVest users that resist Boomburst and other non-Imposter Chansey even harder than Magma Storm. The third slot is for additional coverage. Volt Switch lets Kyurem-B pivot out, letting it maintain offensive momentum and keep up the pressure on its typical counters while also dealing sizable damage to Water-types. Freeze-Dry specifically beats Water-types such as Primal Kyogre and Mega Gyarados and grants Kyurem-W a STAB move to use even if its ability is nullified, against a Pokemon like Giratina. Draco Meteor is a powerful secondary STAB move, but its Special Attack drop leaves Kyurem-W vulnerable afterwards. The last slot is mainly used for utility. Switcheroo is a great option, as this set is a very tempting lure for Soundproof and Steel-type walls that are very crippled by receiving Choice Specs. It also removes Assault Vests and Eviolites, making it easier for Kyurem-W or its teammates to break down opposing walls. However, it makes Kyurem-W more difficult to Imposter-proof against Choice Scarf users, as they can take advantage of it to Switcheroo their Choice Scarf onto your Imposter-proof Pokemon. Extreme Speed can also be used with a Rash nature so Kyurem-W can act as a revenge killer. However, its Extreme Speed is quite weak compared to that of other typical -ate users and is risky to be locked into. Knock Off is another option to remove items without forcing Kyurem-W to lose its Choice Specs, surprising and crippling Assault Vest users and Fur Coat Chansey. Finally, Moongeist Beam can be used for a better matchup against Shedinja and to hit Mega Slowbro and Giratina for decent damage.
Set Details
Refrigerate is a must, providing Kyurem-W with the immensely powerful boosted and risk-free Ice-type Boomburst. Choice Specs amps up Kyurem-W's power, letting it secure important OHKOs against bulky foes such as Giratina, Zygarde-C, Mega Audino, and Dialga, as well as 2HKOs against bulky Pokemon that resist Boomburst and Fur Coat Chansey after Stealth Rock. This makes Kyurem-W incredibly difficult to switch into. Modest is the best nature, as it further boosts Kyurem-W's power. The extra Speed boost from Timid isn't particularly necessary, as the only thing it achieves is the guaranteed outpacing of maximum investment base 90 Speed Pokemon, which are rare and would not stay in anyway.
Usage Tips
Kyurem-W exemplifies a hit-and-run playstyle, as it is immensely powerful and even has the bulk to come out on top in many one-on-one situations where it cannot OHKO the target but is quite easily revenge killed by faster or stronger attackers or walled by defensive foes after it takes down an opposing Pokemon. Bring it in with slow pivot attacks, especially as the chip damage can sometimes be enough to bring would-be checks and counters into KO range, and Kyurem-W absolutely needs to conserve its health to take on foes such as Imposter Chansey, Xerneas, Mega Mewtwo Y, and Mega Gengar. Use Volt Switch to scout opposing Pokemon for support moves, especially Core Enforcer and Knock Off, the former of which deals super effective damage and neuters Refrigerate and the latter of which removes Choice Specs, both stifling a core source of Kyurem-W's power. Also, though it is not completely stopped by status, Kyurem-W should still avoid paralysis, which prevents it from outspeeding and KOing base 90 Speed Pokemon such as Primal Groudon. Once in, it is vital that Kyurem-W commits itself to the correct move. Boomburst is a pretty riskless, powerful move, so it can generally be freely used. Even Ice checks such as specially defensive Registeel and Solgaleo can be chipped into 2HKO range with the help of teammates. In safer situations where it is unlikely the foe will deal much damage back, it might be a good idea to use a coverage move or a Dragon STAB attack to nail potential Steel- and Water-type checks as they come in or use Volt Switch to pivot out to a teammate. Switcheroo can also be used to cripple counters as they come in, but this is generally only useful against more offensive teams where added power is unnecessary or when Kyurem-W's team cannot break through said counters otherwise. Volt Switch is a great move early-game, as no Ground-types will switch in to block it, and it can be used to scout for abilities like Soundproof on Pokemon coming in that would otherwise be unable to counter Kyurem-W as well as the aforementioned Core Enforcer and Knock Off. Maintaining offensive momentum is key to ensure the safest and fastest breaking down of opposing walls. Once a foe is successfully taken down, Kyurem-W will likely be forced out by revenge killers or confronted by walls that can handle the move it's locked into, so make sure to have a partner ready to handle them so momentum is not lost.
Team Options
In order for itself to function most effectively, Kyurem-W appreciates slow pivoting to pass it offensive momentum; entry hazard support and control to 2HKO virtually every single defensive counter with Boomburst, including Fur Coat Chansey and Registeel, without having to be worn down itself; and partners to Imposter-proof it, absorb status, and confront eventual revenge killers. There are several viable Pokemon that can fulfill multiple roles at once. Bulky Steel-types such as Registeel, Aegislash, and Solgaleo pair extremely well with Kyurem-W, as they can pivot out to it, set entry hazards, Imposter-proof it, and confront offensive checks such as Mega Diancie. Ghost-types also make great partners, as, in addition to the above, Kyurem-W almost absolutely requires a Shedinja counter, as Shedinja is still one of its hardest counters and will almost certainly result in lost momentum if Kyurem-W locks itself into any move besides Moongeist Beam. Thus, Pokemon such as Giratina, Aegislash, and Mega Gengar also work well, especially as they can all also check Mega Mewtwo X, and Giratina and Aegislash can set hazards and provide slow pivoting support. A Shedinja of your own can also be used to Imposter-proof non-Switcheroo Kyurem-W as well as provide pivoting to bring it in safely. Many of the defensive Steel- and Ghost-types mentioned are also viable Defoggers, and Mega Gengar can even switch in to absorb Toxic Spikes. Because defensive foes need bulk-augmenting items such as Eviolite and Assault Vest to safely confront Kyurem-W, teammates that can remove such items with Knock Off, such as Mega Gyarados, Mega Audino, and Yveltal, pair with Kyurem-W well. RegenVest Mega Gyarados, along with other RevenVest users, are also effective partners to Imposter-proof Kyurem-W, providing momentum and tanking hits. In addition to all of this, Kyurem-W pairs really well with faster offensive Pokemon that capitalize upon its wallbreaking power. In particular, Mega Mewtwo X loves Zygarde-C and Giratina being kept in check, and Mega Mewtwo Y enjoys Dialga, Fur Coat Chansey, and Steel-types being worn down. They can also check and force out more offensive, wallbreaking foes that limit opportunities for Kyurem-W to come in. Stacking -ate users is also a potent strategy, as the combination of Choice Specs Refrigerate Kyurem-W and V-create Mega Diancie can quickly wear down opposing Steel-types and blow through opposing defenses, as most teams only carry one -ate check. Many physical attackers in the metagame especially appreciate Kyurem-W's powerful special coverage. Pokemon such as Poison Heal Regigigas and Primal Groudon form potent wallbreaking cores with Kyurem-W, as Regigigas can quite safely set up against most Steel-types while Primal Groudon simply plows past them. Poison Heal physical attackers such as Mega Mewtwo X work especially well, helping to shrug off status moves and Knock Off while also garnering momentum and safe switches in for Kyurem-W. Finally, many of the aforementioned Pokemon, including Mega Mewtwo X and Mega Gyarados, can also tackle Soundproof walls like Arceus and Mega Slowbro so Kyurem-W can spam Boomburst without fear.
