|Manga Debut||Chapter 1|
|Anime Debut||Episode 1|
|Japanese Seiyuu||Jun Fukuyama|
|English Seiyuu||Greg Ayres|
Haruhiko Endou is a friend of Junpei's and he goes to the same school with him.
He likes to be in peoples' business and he is very talkative. He also sometimes dresses in a dress such as when he is in a competition for best costume. He seems to have a thing for "Twintails".
He creates his own imaginary relationship flag between Junpei and Kanako.
- Junpei and Kanako as childhood friend flag. In elementary school, they were getting along so well that it lead to the I-will-marry-you-when-we-grow-up. (In reality, they had a big misunderstanding related to the Nyamsus doll that Kanako made for Junpei. She even hit Junpei hard.)
- Second flag, during middle school. Junpei and Kanako got distanced between each other. Thus missing each other from the loneliness. (In real case, they both had cold war and not talking with each other.
- The third and last flag, both Junpei and Kanako reunited at the same class during high school. and so they make their promise under the big legendary tree. (In truth, they were continuing their cold war from middle school.)
However, after the Times Square episode, Haruhiko senses a new relationship flag blossoming between Junpei, Kanako and Kaede.
He is also seems to be a cunning person. During their class trip to Kyoto, he cooperates with Kouta to trick Kaede and Sumiyoshi into following Junpei. His perverted side was also shown during the class trip.