Mashiro Arisaka is a main character in the series Ao no Kanata no Four Rhythm. A cute, cheerful and lively underclassman at Kunahama Academy who admires Misaki Tobisawa greatly. She honestly expresses what she feels. At times though, she can be childish and tends to do child-like facial expressions. Mashiro is also an otaku and a gamer and is very reserved about what she feels. Her birthday is on February 14. Her favorite food is Corn and whipped cream. She's 148cm tall.
- When Mashiro saw Misaki for the first time when class has ended she ran toward Misaki because she missed her, when she suggested to eat Udon, but Misaki says that she can't because she has to help Asuka Kurashina. That moment, Mashiro was first mad but then said she was going with them.
- Mashiro can get a little jealous sometimes when others become too close or friendly with her. For an example, Mashiro was jealous of Asuka because of how close she was to Misaki.
- Mashiro even considered becoming a Fighter because Misaki was one.
- Mashiro deeply cares, loves and respects Misaki to the point that she follows her almost everywhere.
- Mashiro usually takes care of Misaki in the mornings when she is sleepy.
- Mashiro often asks Misaki if she wants to go home with her, and Misaki also likes Mashiro's Udon shop.