Mega Rayquaza is one of the most fearsome wallbreakers and setup sweepers in the metagame thanks to its outstanding base 180 offensive stats and its great speed. It has access to a plethora of powerful offensive moves such as Dragon Ascent, Draco Meteor, V-create, Extreme Speed, and Earthquake coupled with great setup moves in Dragon Dance and Swords Dance. Its attacking moves allow it to have near-perfect coverage at all times, meaning that finding checks to it can be quite the task. Mega Rayquaza does not need to hold a Mega Stone to Mega Evolve, meaning that it can run a variety of more optimal sets such as a Dragon Dance sweeper, a mixed attacking wallbreaker, and a Choice Scarf revenge killer due to this increased flexibility. Its Dragon / Flying typing coupled with Delta Stream allows it to switch in on quite a few offensive threats such as Primal Groudon, Arceus-Ground, and Excadrill if they revealed to not have Dragon- or Ice-type attacks, meaning it provides good defensive synergy on more offensive teams.
However, even after Mega Evolving, Mega Rayquaza still gets outsped by quite a few offensive Pokemon such as Arceus, Mega Gengar, and Marshadow if Mega Rayquaza doesn't have any Dragon Dance boosts. This often means that Mega Rayquaza has to rely on priority moves such as Extreme Speed to revenge kill faster targets, which is especially troublesome versus Arceus, as it can act first with its own Extreme Speed.
Dragon Dance is a great setup move that boosts both Mega Rayquaza's Attack and Speed stats, turning it into a deadly sweeper. Dragon Ascent is Mega Rayquaza's main STAB option that allows it to deal heavy damage against targets that do not resist it. It also enables Rayquaza to Mega Evolve. Earthquake is a great coverage option that allows Mega Rayquaza to hit targets that resist Flying-type moves such as Arceus-Rock, Solgaleo, and Zekrom and can also hit Primal Groudon for more damage. V-create is another coverage option that hits Steel-types that deal with Earthquake such as Skarmory, Celesteela, Ferrothorn, and Bronzong and also is able to OHKO Arceus-Steel. However, the Speed drop is somewhat unfortunate when trying to boost with Dragon Dance. Extreme Speed is a great move that allows Mega Rayquaza to hit faster targets such as Mewtwo, Deoxys-A, Sucker Punch Yveltal, and weakened Arceus to avoid taking its Extreme Speed if Mega Rayquaza gets a boost.
Life Orb is equipped to amplify the damage output from Mega Rayquaza's attacks, as it allows Mega Rayquaza to 2HKO bulky walls such as Yveltal and Arceus-Fairy more consistently. Lum Berry can be used to prevent Mega Rayquaza from being statused for one use by curing conditions such as burn, poison, and paralysis, which can otherwise hamper its ability to sweep and gives it a much easier time setting up. EVs are invested in Attack and Speed with an Adamant nature to maximize the sweeping capabilities of Mega Rayquaza. 4 EVs have been placed in Defense in order to give Genesect a Special Attack boost from Download.
Mega Rayquaza could set up Dragon Dances near the end of the match, as it can sweep more effectively when Stealth Rock is set up and when walls such as Arceus-Fairy, Giratina, and Lugia are weakened first. On the other hand, it could dent teams early on, allowing other potential setup sweepers on your team such as Xerneas and Arceus-Ghost to clean up late-game. Try not to set up against Pokemon that tend to run status moves or phazing moves such as Arceus-Water, Lugia, and Primal Groudon, as they can prevent Mega Rayquaza from sweeping, especially if it is not running a Lum Berry. However, if Mega Rayquaza is holding a Lum Berry, then it can get the chance to set up against the aforementioned threats without risking being statused for one turn, although it still must OHKO these threats after a boost to avoid the status. Mega Rayquaza should also be wary of setting up if the opposing team carries faster priority users such as Arceus, as Arceus can revenge kill Mega Rayquaza if it is weakened, as Mega Rayquaza can often not deal enough damage with its own Extreme Speed to KO the Arceus first. If opposing revenge killers are still active, try not using Dragon Ascent too liberally as well, since the Defense drops can give revenge killers such as Extreme Speed Arceus the opportunity to KO it more easily.
Specially defensive Primal Groudon is a great partner for Mega Rayquaza, as it can soak up status conditions such as burn and paralysis thanks to its typing. Primal Groudon can also set up Stealth Rock and can switch in against Fairy-types that threaten Mega Rayquaza out such as Arceus-Fairy and Xerneas and threaten them out. Hazard removal from Pokemon such as Arceus-Water and Arceus-Fairy is also beneficial to Mega Rayquaza, as it can be worn down rather quickly if it switches into Stealth Rock too often. Entry hazard setters are also recommended, as Stealth Rock allows Mega Rayquaza to KO foes such as Arceus and Multiscale Lugia more reliably due to the chip damage. It also allows Mega Rayquaza to revenge kill offensive threats such as Focus Sash Deoxys-A with Extreme Speed if Psychic Terrain is not up. Spikes users such as Ferrothorn can also be a nice asset, as after two layers, Mega Rayquaza can easily OHKO many targets with a +1 Dragon Ascent such as Arceus-Water, Lunala, and defensive Xerneas. Other wallbreakers such as Yveltal, Marshadow, Ho-Oh, and Xerneas are great teammates as well, as they can apply even more offensive pressure to the opposing team. They also break through Mega Rayquaza's common answers such as Arceus-Fairy, Giratina, and Lugia. Steel-types such as Arceus-Steel and Magearna are also valuable teammates due to their ability to switch into Fairy-, Ice-, and Dragon-type moves.
Draco Meteor is a powerful special STAB move that allows Mega Rayquaza to KO physically defensive targets such as Giratina, Zygarde-C, and physically defensive Yveltal after Stealth Rock damage upon luring them in. Dragon Ascent is Mega Rayquaza's other powerful STAB move that hits Fairy-types, which are immune to Draco Meteor. It can also be used to hit specially defensive walls such as Primal Kyogre and Ho-Oh and is more spammable compared to Draco Meteor due to it not lowering any of Mega Rayquaza's offensive stats after it is used. However, it is worth noting that Draco Meteor still does more damage compared to Dragon Ascent versus targets such as Primal Groudon and Arceus-Water. V-create is a hard-hitting coverage move that allows Mega Rayquaza to hit defensive Steel-types such as Ferrothorn, Celesteela, and Skarmory, which resist both of its STAB attacks. Extreme Speed allows Mega Rayquaza to hit faster targets such as Choice Scarf Xerneas and Mewtwo, making it harder to revenge kill.
Life Orb is equipped to maximize Mega Rayquaza's wallbreaking capabilities, helping it secure OHKOs on specific threats. A Naughty nature is used to give Mega Rayquaza more physical power while not hindering its Special Attack stat as well. It also drops its Special Defense over its Defense in order to ensure Mega Rayquaza takes the least amount of damage from Extreme Speed Arceus. A Naive nature can also be chosen to not hinder Mega Rayquaza's offensive stats while still letting it outspeed threats such as Adamant Mega Rayquaza. The EVs allow Mega Rayquaza to increase its Attack and Speed, making it a fearsome wallbreaker.
Mega Rayquaza is best utilized as an early-game wallbreaker, as giving it a free turn to switch in can drain so much momentum from the opposing team as they struggle to find a switch-in. Also, since this Mega Rayquaza set does not carry any boosting moves, it does not need to remain as healthy throughout the match, meaning switching it in more liberally is encouraged. Because this set cannot boost Mega Rayquaza's Speed, this leaves it easily revenged killed by quite a few offensive threats such as Extreme Killer Arceus, Choice Scarf Lunala, Mega Gengar, and maximum Speed Arceus-Fairy, so be wary on leaving in Mega Rayquaza against these Pokemon. Mega Rayquaza can lure in defensive walls such as Zygarde-C, Giratina, and physically defensive Yveltal that would wall the purely physical sets, and is able to OHKO them with Draco Meteor after Stealth Rock. Since Mega Rayquaza gains an abundance of stat drops from the use of its two main STAB moves, it's advised to use this set to wallbreak instead of sweep.
Primal Groudon is a useful partner for Mega Rayquaza, as it can run a Rock Polish + Swords Dance set, which appreciates the wallbreaking capabilities of Mega Rayquaza breaking down many common answers to Primal Groudon such as Giratina, Arceus-Water, and Quagsire. Primal Groudon synergizes greatly with Mega Rayquaza, as it can deal with both Fairy- and Steel-types such as Xerneas and Arceus-Steel, which can otherwise disable Mega Rayquaza from wallbreaking. Setup sweepers such as Geomancy Xerneas, Calm Mind Lunala, and Swords Dance Arceus-Ground can help Mega Rayquaza break down checks to it such as Lugia, Ho-Oh, Arceus-Rock, and Arceus-Fairy. They also help apply more offensive pressure to the opposing team, which is very beneficial when facing more defensive teams as well. Steel-types such as Arceus-Steel and Magearna can also be great partners to have, since they can switch into Fairy-, Dragon-, and Ice-type moves that would threaten out Mega Rayquaza. Hazard removal from Pokemon such as Arceus-Fairy and Giratina can be a great asset for Mega Rayquaza, as entry hazard chip damage + Life Orb recoil can really limit the sustainability of Mega Rayquaza throughout the course of the match. Entry hazard setters such as Primal Groudon and Arceus-Fairy can help Mega Rayquaza secure crucial KOs on specific targets such as Multiscale Lugia, Yveltal, and Ho-Oh. They help Mega Rayquaza's wallbreaking capabilities.
Dragon Ascent is Mega Rayquaza's main STAB move and deals a large amount of damage with the Choice Band equipped. It is also required to allow Rayquaza to Mega Evolve. Extreme Speed is a great coverage move that allows Mega Rayquaza to hit faster threats such as Mewtwo, Yveltal, and Deoxys-A, making Mega Rayquaza much harder to revenge kill. V-create is another great coverage option that allows Mega Rayquaza to KO Steel-types such as Arceus-Steel, Skarmory, Ferrothorn, and Celesteela, as these Pokemon resist Mega Rayquaza's main STAB moves. Outrage is a secondary STAB move that helps with beating Giratina, Zygarde-C, and Rock-types such as Arceus-Rock and Tyranitar. It also functions as a move to late-game sweep with if Mega Rayquaza can't afford Defense drops, though you should look out for Fairy-types, such as Xerneas and Arceus-Fairy. Waterfall is a usefulmove to revenge kill Primal Groudon if Delta Stream is up due to it being able to survive any of Mega Rayquaza's other moves at full health. It also can be used to hit other Fire-types such as Ho-Oh as well to avoid the negative effects of Dragon Ascent and defensive Arceus-Rock, as it can avoid the 2HKO from Dragon Ascent otherwise. However, the opponent will likely know that it is Choice Band Mega Rayquaza after seeing it be used.
Choice Band Mega Rayquaza is used to deal massive damage initially without needing to setup. Maximizing the EVs in Attack allows Mega Rayquaza to hit as hard as possible, being able to break through many walls with the Choice Band. Speed is also fully invested to allow Mega Rayquaza to outspeed as many threats as it can to avoid the use of Extreme Speed. The Adamant nature allows Mega Rayquaza to hit devastatingly hard and KO threats such as uninvested Arceus and Geomancy Xerneas after Stealth Rock chip damage. A Jolly nature can also be utilized to allow Mega Rayquaza to outspeed threats such as Adamant Mega Rayquaza while still making it able to 2HKO most defensive threats. 4 EVs are also invested in Special Defense in order to prevent Choice Scarf Genesect from revenge killing Mega Rayquaza as easily due to it gaining the Special Attack boost from Download.
Choice Band Mega Rayquaza thrives on breaking through more defensive teams, so safely bringing it in versus walls that cannot damage it too much such as Lugia, Ferrothorn, and Arceus-Water can be a nightmare for your opponent to deal with afterwards. Knowing the exact Arceus formes that the opposing team is carrying can be beneficial, as formes such as Arceus-Steel and Arceus-Rock can capitalize on the defense drops from Dragon Ascent. Arceus-Ghost can also use Mega Rayquaza as setup fodder if it is locked into Extreme Speed. Try to avoid locking Mega Rayquaza into Extreme Speed and Waterfall too often, as threats such as Xerneas and Arceus can take advantage of Mega Rayquaza being locked into these moves and might begin starting to set up themselves. Mega Rayquaza can also be preserved as a check to setup sweepers, as Choice Band Extreme Speed usually deals quite a bit of damage versus targets such as Geomancy Xerneas and Dual Dance Primal Groudon.
Setup sweepers such as Geomancy Xerneas and Calm Mind Arceus-Steel appreciate the wallbreaking capabilities of Choice Band Mega Rayquaza, since it can be a great way to dent defensive teams that would otherwise be able to cope with the aforementioned setup sweepers. They also can weaken checks to Mega Rayquaza such as Zygarde-C and Arceus-Fairy. Entry hazard removal can be a great asset to Mega Rayquaza, as it does not appreciate receiving chip damage from Stealth Rocks that much. Arceus-Fairy, Giratina, and Arceus-Water are all great hazard removers that pair well with Mega Rayquaza. Mega Rayquaza benefits from entry hazard setters such as Primal Groudon and Arceus-Fairy, as the chip damage on the opposing team can help Mega Rayquaza secure the OHKO or 2HKO on walls that it would otherwise not be able to such as Lugia, Arceus-Fairy, and Zygarde-C. Arceus-Rock checks such as Primal Kyogre, Arceus-Ground, and Zygarde-C are also beneficial due to it being one of the more consistent Choice Band Mega Rayquaza answers for defensive teams. Pokemon that can check Fairy-types such as Primal Groudon, Arceus-Steel, and Solgaleo can all be great partners as well, as Mega Rayquaza has a hard time dealing with threats such as Choice Scarf Xerneas, Arceus-Fairy, and Clefable. Primal Groudon is exceptionally useful, as it can absorb status conditions such as paralysis and burns, which would otherwise cripple Mega Rayquaza. Cleric support from teammates such as Clefable and Chansey helps Mega Rayquaza if it receives a status condition, which hampers its use by a lot.
Dragon Ascent is Mega Rayquaza's main STAB move and allows it to deal significant damage versus targets such as Clefable, Yveltal, and Arceus. It is also necessary for Rayquaza to Mega Evolve. V-create complements Mega Rayquaza's STAB moves well, as it allows Mega Rayquaza to targets Steel-types such as Skamory, Ferrothorn, and Celesteela. Outrage acts as Mega Rayquaza's secondary STAB move, allowing it to target foes that resist its Flying-type attacks such as Arceus-Rock and can also hit Dragon-type walls super effectively such as Arceus-Dragon, Giratina, and Zygarde-C. Earthquake is another great coverage move that allows Mega Rayquaza to hit threats such as Arceus-Rock, Primal Groudon, Solgaleo, and Magearna for more damage.
With a Choice Scarf equipped, Mega Rayquaza becomes one of the fastest pokemon in the metagame, outspeeding threats such as Arceus, Mega Gengar, Mewtwo, and Deoxys-A, which it is not able to normally. EVs are maximized in Attack and Speed to enable Mega Rayquaza to hit as hard as possible while also letting it outspeed as many Pokemon as it can. A Jolly nature was chosen to ensure it outspeeds most Geomancy Xerneas at +2 and Deoxys-S.
Choice Scarf Mega Rayquaza is a great lure against offensive threats that would normally outspeed it like Mega Gengar, Deoxys-A, and Arceus, so being able to bluff this can be extremely advantageous. This set can be best utilized late-game after bulky walls such as Lugia, Arceus-Fairy, and Arceus-Water are weakened, due to Mega Rayquaza being incredibly difficult to revenge kill bar priority with its unrivaled Speed stat with a Choice Scarf. The opponent can capitalize on Mega Rayquaza being locked into moves such as Outrage, as they can bring in a Fairy-type such as Xerneas or Arceus-Fairy and proceed to start setting up. Choice Scarf Mega Rayquaza also excels at luring in weakened setup sweepers such as Geomancy Xerneas after they have setup, since in most instances, the opponent will not expect it. With Stealth Rock up, Choice Scarf Rayquaza can usually sweep Psychic Terrain-based teams easily. Thus, ensure it isn't sent in prior to Stealth Rock being set up against these type of teams.
Primal Groudon is a decent partner for Mega Rayquaza, as it is able to deal with Fairy- and Steel-types that can handle Mega Rayquaza such as Arceus-Fairy and Solgaleo. Primal Groudon can also act as a sponge against status moves such as Will-O-Wisp and Thunder Wave thanks to its typing. Setup sweepers such as Arceus, Geomancy Xerneas, and Calm Mind Arceus-Steel are all great teammates as well, as they appreciate Mega Rayquaza's capability against fast offensive threats, while these setup boosters can break though Mega Rayquaza's answers in return. Entry hazard setters such as Primal Groudon, Arceus-Fairy, and Excadrill can be great partners, as Mega Rayquaza appreciates the chip damage from entry hazards to break through specific walls such as Lugia, Ho-Oh, and Arceus-Fairy. Hazard removers such as Arceus-Water and Giratina can also be useful, since Mega Rayquaza does not appreciate repeatedly switching in on Stealth Rock.
A Swords Dance set with Swords Dance / Dragon Ascent / Extreme Speed / Earthquake with a Life Orb is great at breaking down defensive teams much quicker. However, it does get somewhat outclassed by the Dragon Dance set and Extreme Speed Arceus due to the former's ability to boost its Speed and the latter's more powerful priority being beneficial at sweeping more offensive teams, although it still works great in tandem with Sticky Web. Choice Specs Mega Rayquaza is also an option, as it can comfortably OHKO many threats such as defensive Yveltal, Giratina, and Arceus, although the mixed Life Orb set is more beneficial most of the time due to its increased flexibility. However, all Mega Rayquaza sets must carry Dragon Ascent, wasting a moveslot for this set. A bulkier Dragon Dance set with 240 Atk / 104 Def / 164 Spe and an Adamant nature can be used, which trades speed for bulk, helping Mega Rayquaza set up versus more offensive threats. Regular Rayquaza with Dragon Dance + Flyinium Z can also be surprisingly useful, as Supersonic Skystrike can OHKO many walls such as Lugia, Clefable, and Arceus-Fairy with one boost after Stealth Rock chip damage. It also has the added niche of not using up your team's Mega slot, meaning Rayquaza can wallbreak alongside one other Mega Evolution such as Mega Gengar or Mega Lucario. Dragon Dance Mega Rayquaza can also hold a Chilan Berry, which allows it to avoid being revenge killed by Extreme Speed Arceus.