Eri Yamanaka serves as a left defenseman for the Kushiro Snow White women's ice hockey team. Hailing from Kushiro City, Hokkaido, she stands 158 cm tall with auburn hair and aubergine-colored eyes. Her birthday is June 15, and she is right-handed.

As a member of the Snow White team, Eri played alongside Yu Kiyose before Yu's departure. She embodies the team's contrasting philosophy that prioritized individual skill over collective teamwork, a key factor in Yu's initial disillusionment with hockey. Her position as a defenseman places her directly against offensive players during games.

Eri reappears during a critical match between Snow White and the Nikko Dream Monkeys, where Yu now plays. Before the game, Eri encounters Yu and directly addresses her abrupt exit from Snow White. This confrontation highlights the unresolved tensions from Yu's departure and underscores the differing views on team dynamics between them. Eri voices the Snow White sentiment that individual prowess should outweigh team cohesion, the very viewpoint Yu rejected.

In the match, Eri participates in the Snow White defense facing the Dream Monkeys' offense. Her presence on the ice acts as a direct challenge to Yu, forcing Yu to confront her past choices and solidify her commitment to teamwork with her new team. Eri's interaction during this event serves as a catalyst for Yu's continued growth and the affirmation of her new team identity.