Chigusa Kumagai attends Kurikawa High School as a dedicated member of its climbing team. Her appearance features a light tan complexion, brown eyes, and brown hair styled in odango buns. She possesses a notably muscular physique, with exceptional arm strength defining her climbing identity. This earned her the nickname "Muscle Maxima'am," enabling her to tackle difficult terrain using predominantly arm power. She pulls herself forward with sheer hand strength, bypassing complex techniques or full-body maneuvers others might require.

At the Kanto Bouldering Championship, Chigusa advanced through preliminary rounds into the semifinals, securing second place. She ultimately ranked fourth or fifth in the finals. Her performance, alongside teammate Chinari Iwamine’s efforts, decisively secured Kurikawa High School’s team championship victory.

Her surname, Kumagai, combines the characters for "bear" (熊) and "valley" (谷), translating to "bear valley." Her given name, Chigusa, merges "thousand" (千) and "grass/herb" (草), meaning "thousand grass."