Bertha, a member of the Elite Four, will be the second trainer you face in Pokémon Brilliant Diamond and Brilliant Pearl. She will have a collection of Ground and Rock-type Pokémon, which means your Water-types should be the protagonists of the battle. Here are which Pokémon you will face and which ones work effectively against them.
Which Pokémon does Bertha Elite Four have?
In Bertha's group, expect to see four Ground-types and one Rock-type. In the order they are taken out, you will fight Quagsire (Lv. 55), Sudowoodo (Lv. 56), Whiscash (Lv. 55), Golem (Lv. 56), and Hippowdon (Lv. 59). Although Sudowoodo is the only Rock-type, this Pokémon is also weak to Water Pokémon and moves. Bring a sitrus berry to regenerate health, so be sure to use your strongest water attack on them.
The toughest challenge will likely be fighting Hippowdon, with Bertha eventually lending him multiple full resets. Your best strategy to prevent Hippowdon from beating your entire team during this time should be to freeze him with ice moves. Using them repeatedly is very beneficial, as it will keep Hippowdon frozen and provide a super effective attack.
The best Pokémon to use against Bertha in the Pokémon League
Rock-type and Ground-type Pokémon share two common types of weakness: Pokémon Water and Grass. Aside from Empoleon, the two best Water-type options for the Elite Four are Gyarados e Tentacruel - both found in the stretch of water between Victory Road and Sunyshore City. While not the strongest, giving these Pokémon TMs like Waterfall and Surf should help beat most of Bertha's team.
For those without Torterra, a Grass-type that should be in your party is Roselia. In the Sunlit Cavern and Grassland Cave shelters, it should be discovered around level 50 at this point in the game. By capturing him at such a high level, trainers will have access to significant abilities such as Petal Blizzard and Giga Drain, excellent attacks when facing Quagsire and Whiscash.
Related: Is the Battle Frontier in Pokémon Brilliant Diamond and Shining Pearl?