Rokusuke Kouenji is one of the students of class 1-D. He came from a well-known family of scholars. However, he ended up in D-Class for his egotistical behavior.
SpoilerIn Year 1, Volume 11, he watches a scuffle between Hirata and Mii-Chan, which ended with Hirata pushing a desperate Mii-Chan, who was trying to help him, on the ground. Kouenji then intervenes and states his annoyance at Hirata "for treating a girl wrong" referring him as "like a fly, very irritating". His friendship with Mii-Chan is then showed to progress in Year 2, Volume 5, when they are seen walking together often, and Mii-chan referring to him as "someone easy to talk to" when asked about their relationship by Satou and Matsushita."SpoilerDuring the Second Year Uninhabited Island Special Exam, he strikes an agreement with Suzune Horikita, in which he would try for a first-place finish and Suzune would reward him with complete protection from class vote expulsion until graduation and exempt him from being forced to co-operate with the rest of the class, which he wins.
(Source: You-Zitsu Wikia)