Jona

Jona and Rio met at the entrance ceremony. Jona is a bit scared of Rio, since he's Mich's brother. With the time, they both become good friends, hanging out in eachother's houses.

Maia

Maia and Rio met at the entrance ceremony. They don't interact much. Rio thinks Maia's a little bit annoying, while she doesn't really minds his opinion.

Miori

Miori and Rio met at the entrance ceremony. They are good classmates, but not friends yet. They find eachother interesing.

Mia

Rio and Mia at the astronomy club. Mia often feels depressed around Rio. Her reason? He reminds her of a certain person. Rio is very confused by this, but doesn't really mind it.

Ale

Rio and Ale met via Aku. Rio finds Ale annoying to no end, while Ale finds playing with Rio the most entertaining thing in the world. Despite this, they are still friends.

Mich

Mich is Rio's older brother. Since Rio was a pre-teen, their relationship began to deteriorate, mainly because Rio's personality started changing around that time. However, after 2007, this was replaced by a wave of anger. Despite this, Mich absolutely loves his family, including Rio, and he tries to improve their relationship.

Aku

Aku and Rio met via Mich. In the beginning of 2008, Rio lost a bet to Aku, which started NEON FRIDAY. Rio find Aku inmature and annoying, but he is actually Aku's favorite junior along Ale.

Fern

Rio and Fern at the astronomy club. Fern finds Rio the most intelligent 15-year old, like, ever. Rio likes Fern because it's the only senior he can trust on.