This is copy-pasted from the meta discussion thread
Team Origins
For my Trios match v R8 I was scared shitless of Gothitelle as R8 does use it on occasion and any R8 Gothitelle team will be fairly consistent at enabling [insert Gothitelle partner here]. Consequently, I went into the teambuilder and just created a new folder and put pretty much every single idea I had in. Most of these were just team names with the idea so I wouldn't forget, some had mons, but very few had sets.
A team in that folder was called ' Alo + Breakers' that was Alomomola + Primal Kyogre. I was intially slightly hesitant to build with offensive Primal Kyogre though this didn't stem from anything to do with the mon itself. Just before the Open I'd made a post discussing some stuff I'd be paying attention to and specifically mentioned how offensive Primal Kyogre was underused and pretty oppressive to balance structures.
I was a bit concerned about being scouted and whoever I faced prepping quite hard for that. At some point I realized that didn't really matter. I'm probably one of the easiest people to scout as my builder and teambuilding preferences are public. Part of what makes good mons good is that they're good in spite of metagame adaptions to contain them. Building around offensive Primal Kyogre isn't difficult and that lifted the mental block I had. After fiddling with it for a while, nothing seemed to click. After putting it hold for a bit I adapted the team from the Alomomola + Giratina-O core I'd used for the previous team and this is the result.
Team Breakdown
This team isn't particularly unique, but it is fun. There are adaptations I'm sure you'd need for ladder jank, but I didn't test it there. Offensive Primal Kyogre is a demon against balance and some bulky offense teams and is just generally annoying for most teams bar specific flavours of HO and some stall teams. The nuclear power is offset by its lack of recovery, speed, and poor physical bulk. Defensive Primal Kyogre doesn't have these issues, but plays very differently and I wanted a more immediate threat and also just to blast some shit.
This defensive is similar to the one it is based on. This results in the last slot being somewhat free as most offensive breakers in that slot will work fine. I wanted to use Primal Kyogre, but a fast offensive mon such as Eternatus, Marshadow, or Chien Pao work as well and probably better. This teaam isn't unique or innovative, but it is fun.
This is a set I sometimes enjoy using with Stealth Rock Arceus-Fairy and Alomomola. It can work without Alo, but functions so much better with Wish support. This is a weird set, but one I have used before and have been using with increased frequency. The SpD EVs make defensive Primal Kyogre's Ice Beam and 4HKO and allow Primal Groudon to survive offensive Arceus-Ground Judgment after Stealth Rock as base Primal Groudon. The speed is to outspeed paralyzed Zacian though it could go slightly higher as the Atk EVs are largely a dump.
Its main role is to support and wallbreak or slow down offensive mons on balance and bulky offense teams. It will sometimes do that latter with SD, but that is a luxury. It is especially nice against fatter squads. Overheat continues to be great, but Rock Tomb is really nice to slow down Arceus formes, Marshadow, and Eternatus on the switch. Other than that it just does normal Primal Groudon things. The main drawback of the decreased SpD is being unable to tank a Psycho Boost which did come up in R1.
This is the same set I used previously. The Spe outspeeds uninvested Zygarde. The defence lives any +3 Zacian-C hit after Stealth Rock. I can't remember exactly what the SpD was, I want to say +1 Eternatus Fire Blast or something. The remaining EVS are dumped into SpA for some power. Giratina-O synergises so well with alo that the slight bulk reduction isn't noticable as it can easily be healed against anything other than HO. Just an honest and solid mon, especially when you don't have to meticulously manage its HP.
At this point this can be called my standard Arceus-Fairy set. Fitting Stealth Rock on this is what allows that Primal Groudon set to work. It doesn't hate burn but does hate Toxic and Thunder Wave.
Round 4 Game 3 shows just how much work it can put in. It shuts down the opposing Arceus-Fairy due to outspeeding it and Taunt. It switches in effortlessly to Yveltal without having to Recover every time due to the SpD investment.
Bog standard Zygarde. Tera Poison or Dragon Dance might work on this squad. It is mainly there to wall physical things and provide speed control with Glare. It can be a wincon, but it really is here to support the team.
Alomomola is what allows the team to work. Giving Primal Groudon and Giratina-O a second wind allows them to be played so much more freely. Pivoting is also great and is the reason why I won a couple of games. Alomomola is great at bringing your breaker at least once and more, especially against fatter balances. It is somewhat restricting as it wants a decently SpD Arceus-Fairy or Dark For Yveltal. Not an issue because they're great, but Yveltal will be a big threat without those.
It is a very fun breaker. It has a bit of bulk to live CB Marshadow Low Kick and uninvested Precipice Blades after a Rock and Spike.This came into play in
Round 4 Game 3 it let me switch it in safelyish on Primal Groudon with a stored Wish. The speed tier is fairly flexible for a bit of bulk that can go a long way, Primal Kyogre is very flexible.