Kagamine Len is a virtual singer and one of the characters from the Vocaloid software developed by Crypton Future Media. He was released in December 2007, alongside his counterpart, Kagamine Rin. Len is characterized by his youthful appearance, with short blonde hair and a distinctive outfit that includes a yellow tie and headphones. He is often depicted as cheerful and energetic, appealing to a wide audience. As a Vocaloid, Len can sing in various styles and genres, allowing users to create music by inputting lyrics and melodies. He has gained popularity in the Vocaloid community, inspiring numerous songs, fan art, and collaborations with other virtual singers like Hatsune Miku.