• English / United States: Marnie
• Japanese / Japan: マリィ
• Japanese (Romanized) / Japan: Marie
• Japanese (Trans) / Japan: Marie

Marnie is a rival to the player in Pokémon Sword and Shield, who has a competitive side, and together with her partner Morpeko, she aims to become the Champion of the Galar region. She has many passionate fans due to her calm and calculated battle strategies.

Pokémon World Championships Hyper Class Battle vs Ash

Marnie's Grimmsnarl battled against Ash's Gengar during a Hyper Class Battle for the Pokémon World Championships. It can Gigantamax. The hair on is body is also a transformable weapon that is very effective.

Both Trainers had a Dynamax Band on and it was a waiting game to see who would Gigantamax first. Grimmsnarl was the one that ended up Gigantamaxing first while Gengar continued to battle. Realizing that he needed to match its power, Ash got Gengar to Gigantamax. Darkest Lariat turned out to be a bad move for Grimmsnarl as it ended up being swallowed by Gengar causing them to revert to their normal forms. The two charged up their final attacks with Gengar using Shadow Ball and Grimmsnarl using Stomping Tantrum but it was Gengar's move that hit giving Ash Ketchum the victory and increasing his rank to 15.