How do you defecent the Pokemon league in Pokemon Diamond?

Answer 1

I hope by "defecent" you mean "defeat". Anyway, here are the Pokemon League members and tips on how to defeat them. Elite Four Aaron (Bug-Type Master): Dustox Lv53 (Bug-Poison) - Weak to Fire, Flying, Psychic, Rock Beautifly Lv53 (Bug-Flying) - Weak to Rock, Fire, Electric, Ice, Flying Vespiquen Lv54 (Bug-Flying) - Weak to Rock, Fire, Electric, Ice, Flying Heracross Lv54 (Bug-Fighting) - Weak to Flying, Fire, Psychic Drapion Lv57 (Poison-Dark) - Weak to Ground Definitely bring Fire and Flying-Type Pokemon to beat Aaron. Elite Four Bertha (Ground-Type Master): Quagsire Lv55 (Water-Ground) - Weak to Grass Whiscash Lv55 (Water-Ground) - Weak to Grass Sudowoodo Lv56 (Rock) - Weak to Grass, Water, Fighting, Ground, Steel Golem Lv56 (Rock-Ground) - Weak to Grass, Water, Fighitng, Ground, Steel, Ice Hippowdon Lv59 (Ground) - Weak to Grass, Water, Ice Definitely bring Grass and Water-Type Pokemon to beat Bertha. Elite Four Flint (Fire-Type Master): Steelix Lv57 (Steel-Ground) - Weak to Fire, Water, Fighting, Ground Lopunny Lv57 (Normal) - Weak to Fighting Rapidash Lv58 (Fire) - Weak to Water, Ground, Rock Drifblim Lv58 (Ghost-Flying) - Weak to Electric, Ice, Rock, Ghost, Dark Infernape Lv61 (Fire-Fighting) - Weak to Water, Ground, Flying, Psychic Definitely bring Water and Ground-Type Pokemon to beat Flint. Elite Four Lucian (Psychic-Type Master): Mr. Mime Lv59 (Pyschic) - Weak to Bug, Ghost, Dark Girafarig Lv59 (Normal-Psychic) - Weak to Bug, Dark Medicham Lv60 (Fighting-Psychic) - Weak to Flying, Ghost Alakazam Lv60 (Psychic) - Weak to Bug, Ghost, Dark Bronzong Lv63 (Steel-Psychic) - Weak to Fire Definitely bring Bug, Ghost, and Dark-Type Pokemon to beat Lucian. Champion Cynthia (Multi-Type Master) Roserade Lv60 (Grass-Poison) - Weak to Fire, Ice, Flying, Psychic Gastrodon Lv60 (Water-Ground) - Weak to Grass Spiritomb Lv61 (Ghost-Dark) - No Weaknesses, So Use Most Powerful Attack Lucario Lv63 (Steel-Fighting) - Weak to Fire, Fighting, Ground Milotic Lv63 (Water) - Weak to Electric, Grass Garchomp Lv66 (Dragon-Ground) - Weak to Ice, Dragon Definitely bring Ice, Grass, and Fighting-Type Pokemon to beat Cynthia. If you make it this far, you will be entered into the Hall of Fame and become the Sinnoh Champion! Congratulations! If not, just train some more and try again! Either way, I wish you good luck! All credit for this response goes to the Pokemon Diamond/Pokemon Pearl Prima Official Pokemon Scenario Guide, Volume 1.