Moves
Rotom-A's typing, ability, and bulk make it the best defensive spinblocker in the metagame. Rest and Sleep Talk are Rotom-A's only form of recovery outside of Pain Split and prevent it from succumbing to status and residual damage. It also makes Rotom-A a reliable sleep absorber; however, without Shadow Ball, Rotom-A struggles to damage Breloom while getting 3HKOed by Seed Bomb. Rest also gives Rotom-A a massive stock of PP, making it useful for PP staling.
Rotom-A's most prominent attacking move is Thunderbolt, which OHKOes Gyarados. Thunderbolt also hits Steel-types such as Heatran, Metagross, Empoleon, and Scizor and at least 2HKOes Starmie and Skarmory. However, as Thunderbolt is useless against Ground-types and can't hit Breloom well, another option is to use Shadow Ball. Shadow Ball prevents RestTalk Rotom-A from being completely unable to damage Taunt Gliscor while also hitting Ghost-weak targets such as Gengar, opposing Rotom-A, and Starmie hard. For the last slot, Rotom-A can either spread burns effectively with Will-O-Wisp or maintain better coverage with both Shadow Ball and Thunderbolt. Will-O-Wisp is preferred, as being able to burn foes is one of Rotom-A's core niches. It notably is the best response to Tyranitar, as it will not enjoy a burn unless it has a Lum Berry. Will-O-Wisp also limits switch-ins to foes immune to burn damage such as Clefable, Heatran, Camerupt, and Breloom after Toxic Orb activates. Additionally, Natural Cure Pokemon such as Celebi and Blissey can pivot in on Will-O-Wisp. Another option for an Electric-type attack is Discharge, but it suffers from being noticeably weaker than Thunderbolt and potentially giving unwanted paralysis.
Set Details
Rotom-A generally needs all of the physical bulk it can get to stave off Tyranitar, Metagross, Machamp, and Lucario. Take care that absolute maximum HP investment Rotom-A makes its HP stat divisible by 16, increasing the damage it takes from sand and heals from Leftovers. Rotom-A also is at a crowded Speed tier—many Pokemon such as Empoleon, Tyranitar, Swampert, Machamp, and Breloom aim to outspeed minimum Speed Rotom-A. As such, it can invest 56 EVs to outspeed maximum Speed neutral nature Tyranitar, Empoleon, and Swampert. Additionally, Rotom-A can add some Special Defense EVs to better handle special coverage from Swampert, survive Gengar's Shadow Ball, and help prevent Starmie's Rapid Spin; however, going with a fully specially defensive RestTalk Rotom-A is not advised due to its huge Pursuit weakness. A few Special Attack EVs, such as 20 EVs, also help Thunderbolt break maximum HP Breloom's Substitute guaranteed and give better chances to OHKO Starmie and Skarmory.
Usage Tips
Rotom-A should generally be used early to spread burns and block Rapid Spin, preferably before Breloom has activated its Toxic Orb. Rotom-A can lead, as it has good matchups against all common physical leads with the exception of Tyranitar and is immune to Explosion. Mastering the timing of when to use Rest with Rotom-A is critical, as it only has a 24.8% chance to burn physical attackers such as Tyranitar while asleep. Rotom-A should generally be careful about trying to block Rapid Spin too much, as offensive Starmie sets can OHKO Rotom-A with Hydro Pump, while defensive Starmie and Forretress can 3HKO it in sand with Surf and Payback, respectively. Other than these, there are nuances with its usage depending on matchup.
Against offensive teams, Rotom-A is difficult to handle, as foes typically absorb burns with either Heatran, Refresh Swampert, Lum Berry Tyranitar, or Breloom. These teams also typically lack reliable Rapid Spin users, meaning Rotom-A can lean fully into its defensive roll and more recklessly wall opposing physical attackers and spread burns. As Heatran cannot absorb Rotom-A's Thunderbolts forever, aggressively predicting it as it comes in can wear it down easily. Be careful against Metagross and Bronzong, as they can give Rotom-A an Iron Ball with Trick and ruin its ability to handle physical attackers with Earthquake. Despite being able to handle Gyarados, Rotom-A should not be the primary answer, as boosted Gyarados 2HKOes with Waterfall and can make Rotom-A flinch—in addition, Gyarados survives Thunderbolt with a Wacan Berry even after Stealth Rock, meaning it can break through Rotom-A coming in on Dragon Dance. Rotom-A should be kept away from foes that can set up or otherwise take advantage of it, including sweepers with Lum Berry such as Dragon Dance Dragonite and Tyranitar; mixed attackers such as Dragonite, Flygon, and Swampert; Taunt users such as Gliscor; and faster Substitute users such as Substitute + Calm Mind Jirachi and Breloom.
Against more defensive teams, Rotom-A's main value are its ability to block Rapid Spin, huge pool of PP, and handling problem Pokemon such as Skarmory, Breloom, physical Jirachi, and Starmie. Since Clefable is commonly the first switch-in to Rotom-A due to being immune to burn damage, absorbing its Knock Off with Rotom-A is one of the better ways to PP stall it, as Clefable cannot threaten it outside of Calm Mind, and Rotom-A will always be able to use Rest if sand is active. Once Rotom-A goes to sleep, not using Sleep Talk greatly increases how much PP Rotom-A has, to 108 if Rotom-A has Thunderbolt and Will-O-Wisp.
Team Options
RestTalk Rotom-A provides valuable defensive niches and spinblocking. On more defensive teams, it keeps entry hazards up and spreads burns. Spikes setters such as Skarmory and Forretress appreciate this, as neither can prevent Starmie, Donphan, or opposing Forretress from using Rapid Spin. Rotom-A prevents Machamp from spamming Dynamic Punch, meaning prominent Fighting-weak walls such as Tyranitar, Clefable, and Blissey appreciate its presence. Clefable also removes items with Knock Off for adding onto residual damage. Tyranitar provides sand and traps prominent Pokemon that threaten Rotom-A such as Gengar and offensive Starmie. Both Clefable and Blissey can provide cleric support for Rotom-A. All three provide a switch-in to Heatran, which greatly threatens Rotom-A with Flash Fire. Rotom-A is a possible choice on big 5 defensive archetypes over the typical Ground-type alongside Skarmory, Choice Scarf Tyranitar, Clefable, defensive Latias, and Jirachi. Both offensive and defensive Jirachi sets work: offensive sets appreciate the Spikes and residual damage Rotom-A helps to wrack up, while defensive Jirachi helps shore the team against Dragon Dance sweepers such as Dragonite and Tyranitar that Rotom-A struggles with. Defensive Jirachi also enjoys foes worn down due to Will-O-Wisp and appreciates Rotom-A hitting Skarmory hard. Other bulky Steel-types such as Bronzong are great choices, especially for fully Spikes-immune teams. Additionally, Hippowdon, Celebi, and defensive Gyarados can also make solid partners, as they further answer powerful sweepers and are effective with Spikes.
Rotom-A's defensive prowess make it a strong partner for more offensive Spikes-based partners as well, as it has more resilience than more frail spinblockers such as Gengar and Choice Scarf Rotom-A. Alongside Swampert and Skarmory, Rotom-A does not have to worry about Tyranitar as much, as entry hazards wear Tyranitar down, while Swampert at least 2HKOes it. Both offensive and defensive Latias sets are fantastic partners for Rotom-A: Choice Specs Latias hammers Tyranitar and weakens it heavily so that it can’t handle Rotom-A effectively, while defensive Latias's resistances and bulk ease some of Rotom-A's defensive responsibilities against attackers such as Gyarados and Breloom. Choice Scarf Lucario takes on a revenge killing duty against attackers that can set up and OHKO Rotom-A, such as Lum Berry Dragon Dance Dragonite and Dragon Dance Tyranitar. Mixed Flygon is an excellent partner, as its offensive prowess is greatly enhanced by Spikes, and it enjoys Rotom-A switching into Steel-types such as Bronzong and offensive Jirachi and burning them. Empoleon is another excellent partner, as it removes items with Knock Off, and Rotom-A is immune to or resists all of its weaknesses. It also helps against specially offensive Water-types such as Kingdra that Rotom-A cannot deal with. Tyranitar can take on a more offensive role, such as Choice Band to remove special walls or Starmie guaranteed or Dragon Dance to take advantage of Spikes wearing down its answers.