WHAT POKEMON

Well, Aaron, the first of the Elite 4, has all Bug type Pokemon. So Fire type is the best again his team. So any Pokemon like Infernape, Charizard, and other strong Fire type Pokemon will really help you there. Greta, the second of the Elite 4, has Ground type Pokemon. The best type for her team is Grass. I recommend using a high level Meganium, or Venusaur, but that's just me. Use whatever Pokemon you want. Anyway, the third of the Elite 4, Flint, has really a mixed team. Two of his five Pokemon are Fire. Use water type moves on them. Then he also has Steelix, Lopunny, and Drifblim. Use Fighting for both Steelix, and Lopunny. For Drifblim, make sure you do not, I repeat DO NOT, use a physical move to make Drifblim faint, cause of it's ability, Aftermath. Which, when activated, the attacker loses HP. Use a special Dark type move (ie. Dark Pulse) to kill Drifblim.

Ok, on to the final of the Elite Four, Lucian. He has all Phychic type POkemon. Use the Pokemon with the Dark type move(s) that you used to defeat Flint's Drifblim on all his Pokemon. I got to warn you, his Bronzong's defence is insanely high. So I recommend using moves that lower Bronzong's defence status.

Once you defeat the Elite 4, you're still not finished. You have to face Cynthia, the girl who's helped you with Team Galactic, who also happens to be the Sinnoh Champion. Like Flint, she has a large variety of Pokemon. The 6 Pokemon she has are: Spiritomb, Gastrodon, Roserade, Milotic, Garchomp, and Lucario. Her Spiritomb does not have a weakness cause of it's types Ghost and Dark. Just attack Spiritomb with any move that will affect it (ex. Fire). Other types like Normal, or Fighting will not affect Spiritomb. Now, her Gastrodon has the same exact types as Greta's Quagsire, so any attack that is Grass will have a devastating effect on it. Most likely make it faint in one attack if your Pokemon's level is high enough. For her Roserade, use any Fire type attack on it. Now on to Milotic. Milotic is water type (you may know that by now), so use any Grass type move on it. Ok, if you are using Dialga in your team, and if it has Earth Power and Dragon Claw, use Dialga on her last two Pokemon, Garchomp, and Lucario. Her Garchomp will be weak again Dragon Claw, and her Lucario will be weak again Earch Power.

I hope this walkthrough helps,
Sk8rboy

It really just depends on your movesets and how prepared you are for the battles.

I would say ghost and dragon

It really depends on your move set and how prepared you are for battle like what lucraia said...


water type - 2nd and 3rd E4
fire type - 1st E4 and CE4 roselia/lucario
grass type - 2nd E4

You should have Pokemon that know Psychic, Fighting and Ghost moves for the elite four, this covers many of their weaknesses.