OU is the most fundamental tier. It is defined by removing Pokemon from the metagame until the metagame is "not overcentralized" (where the threshold for centralized is kinda arbitrary). In practice, removing all of the fanservice-y cover legends is a good heuristic. We run suspect tests to ban/unban anything that the heuristic fails on.

We consider it desirable to have, for each Pokemon, at least one metagame where it is reasonable to use that Pokemon. Since many Pokemon will be unusable in OU, we stratify the rest of the Pokemon by how often they are used. Each tier is balanced in a similar way to OU (except for experiments like UU). You can expect tiers lower than OU to not be overcentralized.

Anything above OU by definition will be overcentralized. Ubers is the first tier above OU. Assuming M-Ray is banned from Ubers, you can expect the metagame to revolve around Primal Groudon (my best guess, anyway). One could imagine stratifying Ubers by usage similar to OU, although at the moment there aren't enough Pokemon in the tier for this to make sense.

"Anything Goes" (Ubers+) is a philosophically-motivated metagame that does not have any clauses or banned Pokemon. Its existence is enough to ensure there is always a metagame where you can use a particular Pokemon. We do not intend to ever allow Anything Goes matches count towards a Smogon trophy.

This Pokemon/ability/etc unreasonably raises the volatility of Ubers. Think Moody or OHKO spam.

This Pokemon is ~unreasonably~ centralizing. Think 70%+ usage. Even Xerneas was (I think) ~45% usage.

Related to the above point: This Pokemon is obviously in a different power bracket than most of the other Ubers. I argued earlier that M-Ray was in a different power bracket because it is the first ~800 BST Pokemon with a useful ability and unrestricted item.

It is no fun to play or watch matches with this Pokemon/ability/etc (henceforth just Pokemon) allowed. Having this Pokemon in Ubers makes me want to play some other meta. I would be bored as fuck to watch a match with this Pokemon allowed. This is a subjective criterion, but an important one I think: if everyone hates Ubers, then why have it? It is our obligation in such a case to try to fix it.

252 Atk Life Orb Rayquaza Dragon Ascent vs. 4 HP / 0 Def Palkia: 328-386 (101.8 - 119.8%) -- guaranteed OHKO - speed creeps palkia by 1 point and just out right kills it without any boosts

252+ Atk Life Orb Rayquaza Dragon Ascent vs. 0 HP / 0 Def Arceus: 308-363 (80.8 - 95.2%) -- 50% chance to OHKO after Stealth Rock - 50% chance to kill standard Jolly Ekiller after rocks unboosted

+1 252+ Atk Life Orb Rayquaza Dragon Ascent vs. 252 HP / 0 Def Arceus: 460-542 (103.6 - 122%) -- guaranteed OHKO - set up a dragon dance which outspeeds arceus and support without any defense dies

+2 252 Atk Life Orb Rayquaza Earthquake vs. 252 HP / 252+ Def Primal Groudon: 372-439 (92 - 108.6%) -- 50% chance to OHKO - groudon gets outsped at +2 and just dies

252 Atk Life Orb Rayquaza Dragon Ascent vs. 4 HP / 0 Def Mewtwo: 356-421 (100.5 - 118.9%) -- guaranteed OHKO & 252 SpA Mega Mewtwo Y Ice Beam vs. 0 HP / 4 SpD Delta Stream Rayquaza: 266-314 (75.7 - 89.4%) -- guaranteed 2HKO - lives an ice beam from this thing and sets up or kills

+2 252 Atk Life Orb Mega Rayquaza Extreme Speed vs. 4 HP / 0 Def Mega Mewtwo Y: 389-458 (109.8 - 129.3%) -- guaranteed OHKO - ^

+2 252 Atk Life Orb Mega Rayquaza Rayquaza Dragon Ascent vs. 248 HP / 252+ Def Lugia: 390-460 (93.9 - 110.8%) -- 62.5% chance to OHKO - people say Lugia is its 'best counter' and well look at this, consider on an well built hyper offense team the other team struggles to defog so rocks are up

+1 252+ Atk Life Orb Rayquaza Dragon Ascent vs. 248 HP / 252+ Def Lugia: 321-380 (77.3 - 91.5%) -- guaranteed 2HKO after Leftovers recovery - even at +1 the 'wall' dies shows you that Lugia is forced to whirlwind away whilst taking all this damage in the process as it cant really thunder-wave due to if rocks /are/ off then getting followed up +2 252+ Atk Life Orb Rayquaza Brave Bird vs. 248 HP / 252+ Def Multiscale Lugia: 214-252 (51.5 - 60.7%) -- 94.1% chance to 2HKO after Leftovers recovery - which leads to you following up the ko with espeed next turn: +2 252+ Atk Life Orb Rayquaza Extreme Speed vs. 248 HP / 252+ Def Lugia: 191-225 (46 - 54.2%) -- 5.1% chance to 2HKO after Leftovers recovery = dead lugia

For the last 3 or so generations there has been some tension over what exactly Ubers. Is it a tier? Is it just OU's banlist? Is it OK to ban things from Ubers? Well, thanks to GameFreak and Power Creep™, we have some answers for you.- Ubers is now the name for the tier above OU. It is no longer just a banlist.- We are adding a new metagame called(AG). AG has no bans, and no clauses, except for Endless Battle Clause. AG is the spiritual successor to (old) Ubers.- Mega evolving Rayquaza will not be possible in the Ubers metagame.When I first started playing competitive Pokemon, there was no point in playing the Ubers metagame, as there simply weren't enough Ubers for its metagame to be distinct enough from OU. In RBY, the only Ubers were Mew and Mewtwo. In XY, there are currently 50 Ubers--compare that to the 56 strictly OU Pokemon we have at the moment! Next generation we may have MORE Ubers than strictly OU Pokemon, which is a really weird thought. Anyway, the point is: we have enough to try to make a workable metagame out of this set, and considering Ubers to be just a banlist is doing a disservice to the community.Here is how I am constructing the tier system:What are some criteria for banning things from Ubers? We don't quite know yet, but here are some warning signs:Until Ubers has stabilized (and because of the Shadow Tag gaffe) I will personally be overseeing the development of this metagame.There is a lot to say about M-Ray but I will try to keep it short. In general, the Ubers Pokemon hover around ~700 BST; anything higher has either a wasted ability slot (Multitype) or a restricted item slot (Orbs, Plates, Mega Stones). What separates Mega Rayquaza from the rest is the fact that it is. As a result, it is able to easily overpower most Pokemon in Ubers (calcs and description by PROBLEMS ):Questions and comments are welcome, but please do not post saying you want Ubers to return to the way it was. It isn't happening.