Kanna Tanigawa (谷川 柑菜, Voiced by: Kaori Ishihara), is an outgoing girl who is quick to speak her mind. She is a close friend of Kaito, whom she has a crush on. Kaito's sister is aware of this and encourages a relationship between the two. Kanna has been friends with Tetsurō since childhood. She loses her usual demeanor when she gets drunk, and it has some hilarious consequences, like, for example, on the group's trip to Okinawa, interrupting Kaito and Ichika when they were about to share a kiss. A running gag on her is that on special occasions she decides to wear cute clothes to impress Kaito (swimsuit, yukata, etc.) only for Ichika to wear the same kind of clothing and look better than her. Kanna helped Ichika to confess her love to Kaito, at the cost of her own feelings. However, she got over it and confessed her love to Kaito despite the knowledge that he loves Ichika and accepted his rejection with a smile.
Kanna has short blue fluffy hair that cups her face, and blue eyes. Usually, she is seen in bowish clothes such as boy shorts and sports wear. Although, during special occasions when she is around Kaito she tends to dress more girly. In epsiode 8, she is seen wearing a purple yukata with a flower pulling back one side of her hair.
She easily becomes defensive(mostly when her friends are teasing her about the effort she puts in for Kaito), she is also sort of a tomboy, and she might only want Kaito to her self, but his happiness is very important to her. Although shown as very abbrasive to Ichika, she is still a very kind hearted person. Kanna tends to act very strong, yet she gets easily emotional when Kaito favores Ichika over her.