Kei is the Commissioner of the Police department and Satoshi's adoptive father who appears in both manga and anime. He is ruthless (especially to Satoshi) and he has a great obsession of the Hikari's artworks, which is also one of the reasons for him adopting their last descendant, Satoshi. He sent Satoshi back to middle school to spy on Daisuke Niwa and also hired the young prodigy to become Chief Commander of Police and in charge of capturing Dark even though that he always interferes. In the anime, he was the one who found the voodoo doll that is Mio Hio and sent her to the same school as Satoshi to make Daisuke wear a magical pendant in exchange of giving her a real human body. It was also found out that he asked Krad to work for him and help him in awakening the Black Wings by searching for an Ax-like object passed down to the Hikari's, which was later found sealed inside the Hikari Throne(A marble chair with an intact wing on the right and a broken wing on the left) which is found in Satoshi's room inside his apartment. Although he may be cold, it is shown that he once had a soft side to Satoshi(This is shown once by Hio Mio, wherein he complimented Satoshi while he was painting and that he thought of Satoshi before he died). It is not sure if he actually died at the end of the anime after Mio tried to stop him from activating Black Wings.

Some believed that Kei may have some past relations with Rio Hikari, Satoshi's biological mother.