EVs are Effort Values that are points that increase a Pokemon's respective stats. Each four EVs results in a single stat point increase on that respective stat. You can also only have up to 510 EVs at a time so choose wisely. Say you beat a Gyarados and it grants you 2 EVs in Attack. You beat two and you get an extra point in Attack. These EVs (along with IVs and nature) help maximize a Pokemons stats and make it an overall much better Pokemon. Also, since I have no idea how to embed URLs -__- you can click on this link to know more.
https://www.smogon.com/dp/articles/intro_comp_pokemon
Alright, now on the team. It looks like you're new to this so I'll make it a big more informative then my usual rates (...). I also know it's freakin' hard to get good legendaries in games so I'll just work with what's on the platter, no changes to any of the team members. Although you can test this team on Pokemon Online to see if you like it.
Kyurem may have the stats of an Ubers but there's a reason that it isn't used much in Ubers despite that fantastic Ice/Dragon STAB. Nonetheless, you have to play to Kyurem's strengths in order for it to work decently. The best set that it can run in Ubers is a simple
Choice Scarf set. It has a decent 95 base speed. If you have a +Speed nature like Timid or Naive then it serves as a great revenge killer to things like Reshiram, Zekrom, and Shaymin-S. I wish it has one more point in speed though, since it ties with DD Rayquaza D: The best way to play toward Kyurem's strengths is to abuse its fantastic offensive attacks in Ubers. The moves should go along these lines:
Draco Meteor / Ice Beam / Focus Blast / Outrage.
Rayquaza is one of Uber tier's strongest physical attacker. Therefore you should change the moveset to the standard DD set.
Dragon Dance / Outrage / Earthquake / Overheat does great. The items for Rayquaza goes a long way in helping you sweep. A
Haban Berry lets you take a Dragon attack neutrally one time and lets Rayquaza easily take Scarf Palkia's Spacial Rend or Garchomp Outrage and suprise them with your own boosted attack. A
Life Orb could work to help you break past certain walls like Lugia and Groudon after they're past a certain health.
Heatran is a Pokemon that despite what its stats may represent, works better in Ubers as a defensive Pokemon. This is because Heatran has a plethora of resistances and excellent defenses to switch into common moves thrown around in Ubers such as Draco Meteors and Ice Beams. It also sports a hefty 130 base attack stat to not be a sitting duck. A defensive set with
Leftovers of
Lava Plume / Toxic / Taunt / Dragon Pulse does a great job stopping many offensive and defensive threats in the Uber metagame like Blissey and Lugia. A combination of Toxic will cripple walls and Taunt will prevent them from healing, which is why Heatran is often the bane of certain stall teams. Because of Reshiram (and Chandelure) Heatran loses the title of the strongest Fire attacker in the game, so it's best to stick to Heatran's strengths so it will not be outclassed.
I suggest you change Deoxys to the
attack form Deoxys because it simply hits a ton harder with its superior attack stats.
Expert Belt,
Focus Sash, or
Life Orb (choose one) are all excellent items for Deoxys to increase damage output. The best attacks are as follows:
Thunder / Ice Beam / Super Power / ExtremeSpeed. It may seem wierd not to run a STAB attack but Psychic is a horrible offensive typing and the -2 SpA often makes Deoxys less of a threat. Thunder may also seem strange with it's lackluster 70% accuracy, but Kyogre is the most used Ubers Pokemon and with it brings 100% Thunders due to Drizzle. Options likes Recover or Cosmic Power are not good on a Pokemon with base 20 defenses :/
Alright,
Grass Arceus really is an underrated threat. I respect you have it ;D. If you want a support Arceus then
Judgement / Recover / Ice Beam / Thunder Wave is really the best option for it. Paralysis often cripples many Pokemon in the speed-centric Ubers metagame and can turn the tide of the battle easily. Thunder Wave has only one immunity and Groudon the common Ground type is never switching in to Grass Arceus lol. Grass Arceus is really good at its job because it generally walls the most common Pokemon in Ubers, Kyogre (bar Specs Ice Beam D:).
Darkrai is a threat that EVERY team has trouble with. That's testament of how effective it really is. Fantastic Dark STAB with a reliable sleep move and Nasty Plot. What can be better?
Life Orb and
Leftovers are generally the preferred items to run on Darkrai. Your moveset so far is good except for Dream Eater. Dream Eater relies on the Pokemon being asleep and they could just switch out and spite you due to Sleep Clause :p Now, the best option in that slot would be
Focus Blast to utterly destroy Dialga and other steel types.
I wont talk about weakness to other Pokemon or lack of whatever because this has the potential to be a really good team. And the best why to patch up your own weaknesses is to do it yourself. So do yourself a favor, get Pokemon Online, and test the team for youself. Then when you think you have the best darn Ubers team, you can move to Wfi and kill stuff! Even if you don't read this convoluted and lengthy post, do check out the link, because it really is helpful.
