Who designed Pikachu at Ken Sugimori's request?

Atsuko Nishida designed Pikachu at Ken Sugimori's request.

Nishida created the original Pikachu design during development of the first Pokémon games. Ken Sugimori later finalized the design for the game's artwork, which is why both names are associated with Pikachu's creation.

Pikachu was conceived as an Electric-type mouse Pokémon. The character's yellow body, red cheek sacs, and lightning-bolt-shaped tail made it visually distinctive, while its compact form helped it become a natural mascot.

Pikachu was not originally guaranteed to be the franchise's central character. Clefairy was also considered for a prominent role, but Pikachu's appeal to a broad audience helped it become the anime's main partner Pokémon. The anime then strengthened Pikachu's status as Pokémon's global icon.