Kou Yaten (夜天 光, Yaten Kō) is often distant and cynical about everything. Yaten does not like to socialize or do sports. His/her remarks are often sharp-edged and blunt, which further separates him/her from the world. At one point, the other Starlights even chastise Yaten for behaving in a way that might reduce the number of fans] However, he and Luna get along well. At one point during episode 178, Luna inspires Yaten to keep on fighting. In the course of the season Yaten bonds with Minako Aino who takes a liking to him. Their intricate relationship becomes evident in episode 192 where Minako enters an idol audition and Yaten is one of the jurors.
In the manga, Yaten is a female that dresses up as a male. Blunt, and to the point, for example antagonizing Michiru Kaiou for her choice of lipstick. Yaten doesn't interact with the people around her much. She wants to focus on the mission most of all. She is egotistical and nurses grudges, and she hates injury.
In the anime, he has the most spiritual awareness of the Starlights, and is able to tell when Starseeds are taken by Sailor Galaxia. He views humans as untrustworthy and wants to find Princess Kakyuu so they can leave Earth as quickly as possible. This comes further to light when they discover that Usagi is Sailor Moon. Yaten believes that Seiya should stay away from Usagi, despite their wish, shared by Princess Kakyuu and the Guardian Senshi, for them all to work together. His view is shared by Taiki as well as Sailors Uranus, Neptune and Pluto. However, also like Taiki, his views on Usagi change for the better near the end of Sailor Stars. In Yaten's civilian form in the anime, "he" is shown to be WAY WEAKER than Makoto Kino, the strongest of the Guardian Senshi, in her civilian form.
Yaten's responsibilities in the band are background vocals, keyboards, bass guitar, and song arrangement.He also enjoys Photography , but doesn't belong to any school club, preferring to just go home.