KaiLen

KaiLen is the slash ship between Kaito and Kagamine Len from the Vocaloid and Project SEKAI fandom.

Canon
Kaito and Len are both popular characters from the Vocaloid franchise. Many songs have been made using the two of them in the romantic way. However, besides the fan made content, there isn't much content that is canon besides the interactions they have in the Project Diva opening movies. This is because Vocaloids have no canon background, and many Vocaloid fans like to make headcanons for their characters. Shippers often headcannon Len to be in a relationship with Kaito.

Songs
As mentioned previously, many songs have been made using Len and Kaito in a romantic way. One of the most famous songs that have been produced using them is Erase or Zero by Crystal P. The song is about Len and Kaito getting stuck in a time loop, and being faced to confront their feelings for each other. The ending of the song is still up for debate, and fans still theorize this song to this day. Other famous songs include:


 * "The Immoral Memory ~The Lost Memory~" by NatsuP and Haku
 * "FLY AWAY" by ShadowDragonP
 * "Gray Snow" by KID-P, ZankyouP, and CrystalP
 * "More" by Moka

Alternative Songs
Len and Kaito are often used as alternatives to each others songs. As an example, take the song Snowman by Halyosy. Halyosy produced the original version of Snowman with Kaito. But, he made an alternative version using Len instead of Kaito. Both the Kaito and Len versions are available to play in the Project Diva game series. Another song that includes this is Terekakushi Shishunki by Honeyworks. Like Snowman, the original used Len, but an alternative was made using Kaito.

Project SEKAI
Kaito and Len's dynamic varies depending of the SEKAI where they are. In the Street SEKAI Len Makes fun of Kaito because of his easy-going personality, but he still respect him and secretly admire him because of his DJ abilities and loves taking DJ lessons with him. Meanwhile, in the Wonderland SEKAI Len openly respects Kaito because of his maturity.

Fanon
KaiLen is quite popular among the fans and is allmost the most popular slash ship in the Vocaloid fanbase, competing against GakuKai. Despite the fact there isn't many songs depicting them in a romantic way, lots of fanart has been made for the ship. Many people like this ship because of how it looks. Many fans of this ship are already big fans of Kaito and Len, so it would make sense to ship them together.

Despite being a pretty popular ship, it also has generated controversy due the fact that Len is 14 and Kaito, despite not having official age, looks and sounds like an adult. People who ship them either affirm that Kaito is ageless or don't care about their ages as long as they sound well together.

Fandom
FAN FICTION

Trivia

 * Their Kizuna Rank titles include: "Team The Boys", "Male Singers" and "Not Losing to the Songstress".
 * In Project SEKAI, they have alternative duet versions of the songs "Fragile", "Roki" and "Charles".
 * Len has an alternative version of Kaito's song "Doctor=Funk Beat", while Kaito has an alternative version of Len's song "Dappou Rock".