Time for the big mama of Rain Summoners!
HP: 75 / Atk: 75 / Def: 130 / SpA: 75 / SpD: 130 / Spe: 95
Uxie @ Damp Rock
EVs: 252 HP / 252 Spe / 4 Def
- Rain Dance
- Stealth Rock
When you think of "RU Rain Summoner" Uxie is one of the first to come to mind. This thing has titanic mixed bulk (75/130/130 isn't too shabby) and a solid base 95 Speed, allowing it to set up rain with haste. And with Damp Rock, you get 8 turns of Rain for your Swift Swimmers to sweep!
However, Uxie is far from a one-trick pony, which describes many Rain Summoners (Such as Volbeat). Uxie's support movepool is, to put it bluntly, massive. The best one is U-Turn, as it can be used as a great momentum grabber. Also, Uxie's speed is a bit on the slow side, so your U-Turn can go second to ensure a safe switch. And with Uxie's superb bulk, that U-Turn is almost guaranteed. Stealth Rock is another great support option, as it weakens enemy pokes for your Swift Swimmers to break through. Uxie's good speed and defenses make it one of the better Stealth Rockers, as there is a very high likelihood of it getting a safe opportunity to set up. And with only one actually good rapid spinner (screw Sandslash and Cryogonal, they aren't that good) those Rocks are probably there to stay. Yawn is the best option to stop set-up sweepers in their tracks, assuming they don't pack a Lum Berry. It also ensures a safe switch into one of your sweepers, as you force a switch.
This thing, while being amazing, is not perfect. Setup sweepers with Lum Berry get one turn guaranteed to set up as the lack of STAB options leaves Uxie helpless, as Yawn will only burn the berry. Also, if Yawn is utilised (Which it should be) no Heal Bell makes stallers like Clefable or Cresselia with Toxic screw Uxie over, as Uxie has no recovery. A Lack of Heal Bell also leaves Uxie in trouble against Paralysis users, as one of Uxie's more important features is its decent speed. Thankfully, Uxie's counters are few and far between, as Drapion and Spiritomb are it's two biggest counters, and they have lost much of their prominence. Fast taunters like Drapion or Whimsicott is also an issue for Uxie.
Another issue is the fact that Uxie's attacking options are downright pitiful. This can be a problem if you have to keep Uxie in, as even offensive Pokes shrug off Uxie's hits. This also means you'll need a lot of powerful rain abusers to compensate for this offensive letdown.
It is not an overstatement to say that Uxie's movepool is overflowing with moves. You can run Dual Screens, Trick + Scarf, Calm Mind and a myriad of other sets. Unfortunately, there is only 4 moveslots. So, since one is already taken up (Rain Dance) you don't have much room. U-Turn is necessary, so only two are left. Among your options are Heal Bell, Psychic and Thunder Wave but they are usually outclassed by Stealth Rock and Yawn. There are options, but it is best to stick to the above moves. Another Spread that you can use is 252 HP / 240 Def / 16 Spd for more bulk, but this slows down Uxie below the speed of Taunt Drapion.