Sorry about the crappy title, I'm not very creative at that kind of thing.
Team-Building Process
Seeing Reshiram's amazing stats, typing, and coverage, I knew he would be the main sweeper of my team. Obviously, sun makes Reshiram even deadlier, essentially a more offensively-oriented special version of ho-oh, so I added a Groudon lead. I can't have only one sweeper, so I added the even deadlier Mewtwo. I wanted to have spikes and a more dedicated wall, so Nuttre made it to my team. I was also shocked by Shanderaa's potential, so he earned another slot on the team. Scarf ditto looked like a promising late-game sweeper, so I chose to use him.
Groudon @ leftovers
Ability: Drought
Impish nature (+def, - spa)
Evs: 252hp/252def/4spd
-Stealth rock
-Thunder wave
-Roar
-Earthquake
Simple weather support Groudon. Stealth rock is always nice to have, because not many ubers resist it, and it keeps enemy Ho-oh from abusing my sunlight. Roar works nicely with stealth rock, racking up some residual damage when they try to stall or switch to a counter. Thunder wave also gets nice synergy with Roar, crippling any sweepers and supporting some of the slower members of my team. Earthquake is there so that taunt doesn't completely shut me down, and deals some damage even without EVs. To demonstrate, a Darkrai takes a minimum of 59.8% damage from earthquake, a 2hko. As well, a +1 defense Bulk Up Dialga takes 43.6% - 52% damage.
Reshiram @ Life Orb
Ability: Turbo Blaze
Nature: timid (+spe, - atk)
Evs: 4 def/252 spa/252 spe
-Nitro Charge
-Dragon Pulse
-Blue Fire
-Draco meteor
After a Nitro Charge, Reshiram will out-speed every unboosted pokemon other than Ninjask and Deoxys-s. Dragon pulse and Blue Fire are STAB moves of choice for reliability, and thanks to Turbo Blaze, hit every pokemon in the game for at least neutral. Dragon tail is there to break stalls and continue to rack up damage from Stealth Rock, helping to set up for other pokemon.
Mewtwo @ life orb
Nature: timid (+spe, - atk)
Ablility: pressure
Evs: 4 def/252 spa/252 spe
-calm mind
-ice beam
-aura sphere
-psycho break
Calm mind makes Mewtwo a behemoth, nuff said. ice beam hits a lot of the uber tier for SE damage. aura sphere gets decent type coverage with ice beam, hitting the steel-type pokemon for SE damage. Psycho break makes Mewtwo a very versatile wallbreaker. Even though it breaks the 'never use psychic-type moves in ubers' rule, it is worth it on Mewtwo. It essentially gives Mewtwo a base 154 attack stat, and another 252 evs in attack. The move alone makes Blissey's usability in ubers questionable.
Nuttre @ leftovers
Nature: Sassy (+spd, - spe)
Ability: Iron barbs
Evs: 252 hp/4 def/252 spd
Ivs: 0 spe
-Curse
-Spikes
-Gyro ball
-Leech seed
This guy works shockingly well in ubers. Thanks to his typing, he resists thunder, water spout, draco meteor, dark pulse, and shadow ball, all of which are seen on a regular basis in the Uber environment. Curse boosts his massive defense to astronomical levels, and boosts gyro ball, a STAB move that will be 150 BP a lot of the time in the speedy uber tier. Spikes works well for team support. Leech seed makes Nuttre even more annoying, while still gradually regaining HP.
Palkia @ choice scarf
Nature: timid (+ spe, - atk)
Evs: 4 hp/252 spa/252 spe
Moves:
-spacial rend
-thunder
-surf
-fire blast
According to Server Crash, I was kyogre-weak. I decided to use the tried-and-true counter to Kyogre, scarf Palkia. Thunder wards off Kyogre, and the 30 % paralysis chance can mean some hax before the 8 PP wear off. Surf is his reliable STAB move, OHKOing Darkrai in the rain. Spacial rend is for STAB and super-effective hits against the dragons of the uber tier. Fire blast means that palkia can work well in any weather, 2HKOing Groudon.
Ditto @ choice scarf
Ability: Eccentric
Evs: 252 hp
-Transform
-
-
-
The one and only scarf ditto moveset. 252 hp EVs because HP is the only stat that stays after ditto transforms.
Team-Building Process
Seeing Reshiram's amazing stats, typing, and coverage, I knew he would be the main sweeper of my team. Obviously, sun makes Reshiram even deadlier, essentially a more offensively-oriented special version of ho-oh, so I added a Groudon lead. I can't have only one sweeper, so I added the even deadlier Mewtwo. I wanted to have spikes and a more dedicated wall, so Nuttre made it to my team. I was also shocked by Shanderaa's potential, so he earned another slot on the team. Scarf ditto looked like a promising late-game sweeper, so I chose to use him.
Groudon @ leftovers
Ability: Drought
Impish nature (+def, - spa)
Evs: 252hp/252def/4spd
-Stealth rock
-Thunder wave
-Roar
-Earthquake
Simple weather support Groudon. Stealth rock is always nice to have, because not many ubers resist it, and it keeps enemy Ho-oh from abusing my sunlight. Roar works nicely with stealth rock, racking up some residual damage when they try to stall or switch to a counter. Thunder wave also gets nice synergy with Roar, crippling any sweepers and supporting some of the slower members of my team. Earthquake is there so that taunt doesn't completely shut me down, and deals some damage even without EVs. To demonstrate, a Darkrai takes a minimum of 59.8% damage from earthquake, a 2hko. As well, a +1 defense Bulk Up Dialga takes 43.6% - 52% damage.
Ability: Turbo Blaze
Nature: timid (+spe, - atk)
Evs: 4 def/252 spa/252 spe
-Nitro Charge
-Dragon Pulse
-Blue Fire
-Draco meteor
After a Nitro Charge, Reshiram will out-speed every unboosted pokemon other than Ninjask and Deoxys-s. Dragon pulse and Blue Fire are STAB moves of choice for reliability, and thanks to Turbo Blaze, hit every pokemon in the game for at least neutral. Dragon tail is there to break stalls and continue to rack up damage from Stealth Rock, helping to set up for other pokemon.
Mewtwo @ life orb
Nature: timid (+spe, - atk)
Ablility: pressure
Evs: 4 def/252 spa/252 spe
-calm mind
-ice beam
-aura sphere
-psycho break
Calm mind makes Mewtwo a behemoth, nuff said. ice beam hits a lot of the uber tier for SE damage. aura sphere gets decent type coverage with ice beam, hitting the steel-type pokemon for SE damage. Psycho break makes Mewtwo a very versatile wallbreaker. Even though it breaks the 'never use psychic-type moves in ubers' rule, it is worth it on Mewtwo. It essentially gives Mewtwo a base 154 attack stat, and another 252 evs in attack. The move alone makes Blissey's usability in ubers questionable.
Nuttre @ leftovers
Nature: Sassy (+spd, - spe)
Ability: Iron barbs
Evs: 252 hp/4 def/252 spd
Ivs: 0 spe
-Curse
-Spikes
-Gyro ball
-Leech seed
This guy works shockingly well in ubers. Thanks to his typing, he resists thunder, water spout, draco meteor, dark pulse, and shadow ball, all of which are seen on a regular basis in the Uber environment. Curse boosts his massive defense to astronomical levels, and boosts gyro ball, a STAB move that will be 150 BP a lot of the time in the speedy uber tier. Spikes works well for team support. Leech seed makes Nuttre even more annoying, while still gradually regaining HP.
Palkia @ choice scarf
Nature: timid (+ spe, - atk)
Evs: 4 hp/252 spa/252 spe
Moves:
-spacial rend
-thunder
-surf
-fire blast
According to Server Crash, I was kyogre-weak. I decided to use the tried-and-true counter to Kyogre, scarf Palkia. Thunder wards off Kyogre, and the 30 % paralysis chance can mean some hax before the 8 PP wear off. Surf is his reliable STAB move, OHKOing Darkrai in the rain. Spacial rend is for STAB and super-effective hits against the dragons of the uber tier. Fire blast means that palkia can work well in any weather, 2HKOing Groudon.
Ditto @ choice scarf
Ability: Eccentric
Evs: 252 hp
-Transform
-
-
-
The one and only scarf ditto moveset. 252 hp EVs because HP is the only stat that stays after ditto transforms.