Yo, welcome to some teambuilding sessions again with me. Been a while, eh? Anyways, this team was actually built with a user from the pokecommunity server. However, the stuff he suggest got replaced because 1.) they were outclassed, or 2.) they were viable on paper, but not in practice. So really, the only help I had with this was team synergy. Everything that he suggested in THIS CURRENT TEAM WILL BE NOTED. Let's begin, shall we?
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Ok, so I asked my fellow builder what he wanted to build around, a core, or a mega. He chose Mega, and we soon came to another question. WHICH MEGA? Remember, this was prior, or during the early stages of the Aegislash suspect test, so we had Aegislash and MMaw to be able to deal with. Me, in the mindset of 2-3 months ago, I was hoping he's say something like MPinsir, or MCharX (this shit is hard for me to build around), since they are both very high quality Megas. The last thing on my mind was MManectric. To not upset him (Was my first time building with the dude), I just agreed and moved on. Things I didn't know back then was that Mega Manectric shits on Balanced teams and HO that dont run Scarf Ground types.

So Manectric was added, and I suggest a core. Ferrothorn + Gliscor.
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Ferrothorn came first. Since we didn't know who to put hazards on, their movesets were left to the end, but their synergy was built around. turns out, Ferro got the standard role of RockSeeds + beating Mega Gyarados 1v1 (Will explain later). Also, it walls Greninja for Gliscor. Not much to say, except the fact that Ferro isnt the biggest wall on this team, and rather, more of a defensive pivot switch, thanks to Iron Barbs + Leech seed.

Speaking of Leech Seed, dont let that happen when Gliscor comes in...
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Gliscor shits on teams with Scarfed Ground pokemons (Garchomp, Landorus-T), as well as many more. With a pretty fast Taunt, Gliscor is capable of shitting down (oops, shutting down) a ton of status users/set-up users/stall teams. Really basic ToxicRoost stalling that I modified from an original Roost + Protect (No Taunt) Gliscor on the original co-op teambuild. Gliscor is the real mvp, yo.
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Nest is OU's priority bird. Since we didnt have a dedicated sweeper so far, we decided to make Talonflame the standard SD SHarp Beak set. Tempted to run Taun/Will-O-Wisp on Talonflame, I never actually made the change (because every time I did, it failed), however, I did modify it a bit. The original team has Talon to outspeed Thundurus, whereas my version has it to outspeed Raikou and other base 115's. But since you assholes like to counterteam, you can be satisfied with the original spread (P.S. I speed creep on a lot of my non-max speed mons, js). Talon is a really basic sweeper, with the help of Gliscor and Ferro helping it wear down threats, it wins quite many games. However, at this point, I don't have a Defoger... shit lmao.

Originally, we debated on having Gliscor set up SR, while Ferro set up Spikes. This was out of the question once Talon was added, since 2-4 turn of setting up would be blown away in just 1 turn.
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Here it is, the usual Latios. If you need offensive Defog, Latios is your go-to guy. Capable of 2HKO'ing any Azumarill (bar Physically Defensive Azumarill), this buddy really has no switch ins. Originally, we made it a Mixed Latios with Earthquake, to catch common switch ins like Mawile, aegislash, and Heatran off guard. However, with the banishment of both Aegislash AND MMawile, I reverted to Roost, which alowed me to beat and switch into CharY efficiently, granted I'm healthy, and they dont run Dragon pulse. And thanks to one of OU's best Sucker Punch user gone, Latios has an easy time Draco Meteor'ing any Bisharps that switch in, easily leaving them in range for Talon to Revenge Kill.
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Lastly, we have the only changed member of the team, Assault Vest Azumarill. Previously being a CroCune, CroCune admittedly sucked in OU. Sure, it sets up on a ton of stuff, but being susceptible to Knock Off made it less efficient. Also, standard LO Thundurus was still 2HKO'ing after +1 Suicune, so it wasnt worth it, AzuVest, while it cannot switch into Thundurus directly (unless i predict HP Ice), it CAN beat it 1v1. Azu is my second pivot switch, being able to switch into many of OU's mons, such as Greninja. With the help of Ferro's Leech Seed, Azu can potentiall have some recovery, making it a very great asset to the team.