The main protagonist of the series, who is an aspiring children's book artist. Ryūshi moved into Narutaki Sou so he could attend the Sumeragi Design School in Tokyo. Aoba Kozue is his second cousin. He met Kozue when they were younger, but doesn't remember this at the start of the series. He is childish and passive to the point of never objecting when anyone does anything wrong to him, which happens a lot. In the epilogue, he is shown to have married Aoba Kozue, with four daughters, possibly representing Aoba's former personalities.
