He was the first King's Chair of the "Guardians" and their founder. Manages the planetarium as a part-time job. Artist of the artbook "Kokoro no Tamago" (The Heart's Egg). Looks similar to Tadase. At first, he is thought to hold the Humpty Lock. A cat lover and has a liking for Ikuto's cat ears. He plays as a minor character but seems to have a bigger role in the story, considering that it is he who assigns the Guardian Chairs and is often seen counseling Tadase.
He is able to travel through time. It is revealed in the last chapter of the manga that he is Tadase's adult self, traveling through time.
In chapter 48 however, it is shockingly revealed that the man Amu thought was Tsukasa was actually Tadase from the future when Kiseki making it back into the path of stars and calling him "Tadase", the reason why he looks like Tadase is because he is Tadase's mother's brother.