RedBlastoise said:The whole generation including HGSS? Because if so then Whitney was the hardest Gym Leader from the Generation 4 games. But if you mean just Sinnoh then I'd pick Volkner in Platinum because I hated his Electivire and Luxray.
KyogreThunder said:In HeartGold/SoulSilver, Morty is hard to beat because of Hypnosis, and Clair spams Thunder Wave, not to mention Kingdra.
Aduro said:Byron was kinda tricky. Between rest-chesto and iron defence it could become very difficult to take it down with physical moves. Bronzor was packing hypnosis and confuse ray, with solid defences. You needed the right mon to take him down, which was a problem in nuzlockes.
What was in your opinion, the hardest Gym Leader to defeat in this Generation?