OiKage

OiKage is the slash ship between Oikawa Tooru and Kageyama Tobio from the Haikyu!! fandom.

Canon
Oikawa's a 3rd year and Kageyama's a 1st year, both being teammates on the same middle school team: Kitagawa Daiichi Junior High. Both being the same position: setter, the two have been constant rivals from the start. As Oikawa was Kageyama's Senpai, he was the one who taught him a lot of techniques, like the jump serve, which Kageyama still uses to this day, making Kageyama Oikawa's 'protégé'

They met again in Episode 7 of the first season. After Aobajohsai High lost to Karasuno High School's team - of which Tobio was a member - in the same episode, Oikawa sets himself a goal to defeat Karasuno next time, especially Kageyama.

During the match between Karasuno and Aobajohsai, in the Inter-high tournament, Kageyama seems more nervous than the other games already played, and this brings him back to his old habits of King, that make him end up on the bench. When he come back to the court he is more trustful towards his teammates and that's one of the changes Oikawa notice in Tobio. Oikawa and Kageyama, until the end of the game, try to predict each other’s movements that leads Seijoh to the victory. However, they have a rematch during the Spring tournament, Season 2, Episode 20-24, and win. Before they line up, Oikawa goes to Kageyama and tells him not to get cocky, now it's 1-1.

Fanon
Though this isn't the most popular ship for both characters, they are both shipped by fans.

Fandom
FAN FICTION
 * Tooru/Tobio tag on FanFiction.Net
 * Tooru/Tobio tag on FanFiction.Net