Riku (リク) is a member of Trichronika and the bassist of the group.
His twin brother is Kai, who is also in the same band.
Riku is of an unspecified, fox-like species with a pink nose and inner-ear. He has teal eyes and midnight blue hair to match his indigo ears and tail-tip. His hair is straighter but he has the same ahoge as his brother. He wears a mint-colored suit to match his brothers but with long sleeves, matching pants, white shoes with brown sole, and a white shirt with a long red tie.
In the anime he looks the same, but his fox ears are colored to match his hair.
Riku cares a lot for his older brother, and looks up to Shu☆Zo, dreaming of being like him. He is sometimes shy, but hardworking overall.
Although they are twins, Kai and Riku's relationship is kind of hazy. Riku has a tendency of not communicating enough with his twin brother, and sees himself as the worst in the band, feeling like he is always "dragging his feet".