Eiko Yamada, often referred to as Joshidaisei Eko-chan, is a recurring character in the anime series Genshiken. She is a university student known for her vivacious and energetic personality. Eiko is deeply passionate about her interests, which include cosplay and otaku culture. Within the series, she often acts as a bridge between the more introverted members of Genshiken and the outside world, helping to introduce new ideas and perspectives. Her presence adds a lively dynamic to the group, and her enthusiasm is infectious, bringing a fresh energy to every scene she's in.