Origin and Game Appearances
Like his predecessor Hatsune Miku, Len (and his twin sister Kagamine Rin) was not originally a game character, but a voice bank created for Crypton Future Media's Vocaloid 2 singing synthesizer. His voice is designed to simulate a "low-teen" male, with Rin's simulating a female equivalent. Both Len and Rin's vocal template are based on that of Japanese voice actress Asami Shimoda.
Len and Rin first appeared as unlockable custom character skins in Sega's PSP rhythm game Hatsune Miku: Project Diva. To unlock them, players had to play the respective versions of the song "Kouya to Mori to Mahou no Uta" (Song of Wastelands, Forests, and Magic - "荒野と森と魔法の歌") on Normal difficulty and obtain Standard-rank scores, as well as hitting a maximum combo of 100 unbroken notes.
The duo later appeared as fully playable characters in the sequel, Hatsune Miku: Project Diva 2nd, with their own selection of solo songs and duets.
- Len's (and Rin's) surname "Kagamine" are taken from the characters for "Mirror" ("Kagami") and "Voice" ("Ne"), to reflect that the twins and their voices are mirror images of one another.
- Amami Shimoda, the voice actress who provided the template for both Rin and Len, also voiced twin characters in The Idolm@ster series, namely the sisters Ami and Mami Futami.
- The yellow-and-black color scheme of the twins' clothing has been likened by fans to the colors of a road-roller, eventually leading to the composition of the original duet song "That's My Road-Roller!"
- Len's signature item aside from a road-roller is a banana.