A Cthuko (another alien species), who is Nyaruko's childhood friend from kindergarten and elementary school. Instead of thinking of Nyaruko as her enemy (because they're different species, and both Cthuko and Nyarlotephian are enemies), she loves her deeply. Kuko is usually quiet and blushes a lot. She has really perverted thoughts. Nyaruko calls her 'NEET', due to the fact that she loves games.
Later in the 2nd season she starts to like Mahiro more after he played along with her with the fact that she is engaged to him (so she won't marry her cousin).