Beat Elite 4 With one pokemon

First off catch kyogre in cave of origin.

Teach it the following moves:

Thunder
Surf
Ice beam
Waterfall(Or Hyrdro Pump)

So when you get to the elite 4, send out Kyogre.

Sidney and the DARK side:

Mightyena:Surf or Waterfall
Cacturne:Ice beam
Shiftry:Ice beam
Sharpedo:Thunder
Absol:Surf or waterfall or Hydro pump

Phoebe and her GHOST crew:
Dusclops:Surf
Bannette:Surf
Sableye:Surf
Bannette:Surf
Dusclops:Surf

Glacia and her ICY style:

Glalie:Surf or Waterfall or Hydro pump
Glalie:Surf or Waterfall or Hydro pump
Sealeo:Thunder
Sealeo:THunder
Walrein: Thunder

Drake and the power of DRAGONS:

Shellgon: Ice beam
Altaria: Ice beam
Flygon:Ice beam
Flygon:Ice beam
Salamance: Ice beam

Now to confront the champion.....Steven!

Skarmory:Thunder
Aggron: Surf or Waterfall or Hydro pump
Cradily: Ice beam
Clyadol: Surf or Waterfall or Hydro pump
Armaldo: Surf or Waterfall or Hydro pump
Metagross: If you have Hydro pump, use it here. If not, hope your pokeomns strong enough.


And there you go. You beat the Champion!

=dragonrage