Entry location: Sinnoh Elite Four
Here's the Sinnoh Elite Four's weaknesses and Pokemon.
Aaron( Bug Type) = Fire Pokemon/Lightning
Aaron has Dustox, Heracross, Vespiquen, Beautifly and Drapion.
Bertha( Rock Type) = Water Pokemon
Bertha has Quagsire, Hippowdon, Sudowoodo, Whiscash, and Golem.
Flint( Fire Type) = Water Pokemon
Flint has Rapidash, Driftblim, Infernape, Steelix, and Lopunny.
Lucian( Physic Type) = Fire Pokemon
Lucian has Mr. Mime, Medicham, Alakazam, Girafarig, and Bronzong.
Cynthia( Various Types)(Elite Four Champion)
Cynthia has Spiritomb, Garchomp, Lucario, Gastrodon, Milotic, and Roserade.
Cynthia's weaknesses are Lightning, Fire,
Physic and Fighting.