GakuKai

GakuKai is the slash ship between Kaito and Kamui Gakupo from the Vocaloid fandom.

Canon
Kaito and Gakupo are two voicebanks from the voice synthsizer Vocaloid, neither of them has a canon personality or background and their relationship and dynamic depends on the song that they sing together, even so, Kaito and Gakupo has the disadvantage of being from different companies (Kaito is from Crypton Future Media/Yamaha while Gakupo is from Internet Co.), and eventually they don't match in many semi-official stuff, although Gakupo appears in the manga Hatsune Mix.

Songs
Gakupo and Kaito don't have many original duos, much less songs were they are in love, but it is still one of the most used Vocaloid combinations mostly due the fact that they are two of the most popular male vocaloids, and there is a ,ot of covers of them of song like Magnet, Matryoshka and Brain Fluid Explosion Girl. There is also some songs that aren't actual Gakukai duets but show us their dinamic, for example, in The Lunacy of Duke Venomania Gakupo made a pact with the Devil in order to atract all women as possible, until Kaito, dressed as a woman, scammed him and stabbed him in order to get his wife back.

Imitation Black is a saga mostly singed by them, but also by Len, that talk about two vampires that fall in love with a human (Len), but the love between an human and a vampire is forbidden and Len denis to admit his love for them. In one of the songs, Lovelessxxx, Kaito and Gakupo start a relationship because they though that Len didn't care for them, Len saw them having sex and he almost try to kill them, but he isn't able to do that and lost his memeory at the end.

Fanon
Being Kaito and Gakupo two of the oldest male vocaloids ever created, GakuKai is one of the most popular Vocaloid slash ships, if it isn't the most popular, and it has a strong competence against LeKai for the first place, although their threesome with Len is pretty popular too. It is often paired along with LuMiku, and its main rivals are KaiMiku, KaiMei, GakuLuka and GakuGumi.

In AO3 it is the most popular ship for Gakupo and the second for Kaito, only surppased by KaiMei, there is around 130 fanfics of the ship there, and there is also around 1460 works on Pixiv.

Fandom
FAN FICTION

ART
 * がくカイ tag on Pixiv
 * Eggplant-Icecream on Deviantart