Oikawa is the captain and setter for Aoba Johsai High's volleyball club. Kenma is the setter of Nekoma High's volleyball club, making him and Oikawa share the same position. Besides their gender and position, Oikawa and Kenma share a rivalry with Karasuno High. Oikawa went to the same middle school as Tobio Kageyama, making the rivalry more intense. Kenma is less involved with Kageyama, but is best friends with Shōyō Hinata. Kenma's rivalry is also made more intense by the fact that he wants to play a game against Karasuno that isn't a practice match.
The two don't have many similarities, but they have a lot of differences. The most notable difference personality-wise is that Kenma is more introverted while Oikawa is extroverted. Kenma has a hard time making friends while Oikawa is very popular, mostly to female students. Oikawa is very dedicated to volleyball, with it being his occupation in the timeskip. Kenma, on the other hand, doesn't like nor dislike volleyball and joined only because of Kuroo's influence.
Despite all these differences, the two boys are both smart and strategic. They show it mostly during volleyball matches. Kenma's intelligence makes up for his lack of strength and power. Unlike Kenma, Oikawa is incredibly strong and powerful. While their levels of power are different, Oikawa and Kenma share the same statistics for technique and speed; 5/5 for technique and 3/5 for speed.
OiKen is considered a rare pair and it is not well known. Most of this is because the two have never interacted. It is overshadowed by more popular ships with the boys' childhood friends, IwaOi and KuroKen. There are also other ships like KenHina and OiKage that are more popular than OiKen, though they are not as popular as IwaOi and KuroKen. Though, OiKen is popular amongst multishippers and those who like rare pairs.
A popular group in the Haikyu!! fandom that includes Oikawa and Kenma is the "Pretty Setter Squad" that includes, as the name suggests, pretty setters. The squad also includes Tobio Kageyama, Kōshi Sugawara, Akaashi Keiji and occasionally Atsumu Miya. Though, not a lot of people ship the Pretty Setter Squad as a poly ship. Many prefer to ship it as a friendship. Nonetheless, the group contains Oikawa and Kenma and is popular within its fandom.
On AO3, OiKen currently has 84+ works. Fluff is often used in those works, more than angst is. Since there are more popular ships for Oikawa and Kenma, angst is likely used in OiKen works because Oikawa and Kenma are cheating on their partners or trying to move on from them. Though, polyamory is also used, which would cause the opposite of Oikawa and Kenma cheating on their partners. A somewhat common AU that is used for OiKen works is the college or university AU.
|SHIPS||het||BokuYukie • DaiYui • HinaYachi • ShouMika • TanaKiyo • YamaYachi|
|slash||AkaKen • AoFuta • AtsuAran • AsaDai • AsaNoya • AtsuHina • BokuAka • BokuHina • BoKuro • DaiSuga • HinaNoya • IwaKage • IwaOi • KageHina • KenHina • KinKage • KuroKen • KuroTsuki • KuroYaku • Kyouhaba • OiKage • OiKen • SakuAtsu • SemiShira • SugaKage • TsukiHina • TsukiKage • TsukkiYama • UkaTake • UshiKage • UshiTen • UkaTake • YakuLev|
|femslash||KanoYachi • KiyoYachi|
|family||AkiKei • AtsuOsa|
|cargo||Kenma x Video games|
|CHARACTERS||male||Kei Tsukishima • Kenma Kozume • Shōyō Hinata • Tobio Kageyama|