vocaloid

Kagamine Rin & Len are humanoid personas voiced by a singing synthesizer application developed by Crypton Future Media, headquartered in Sapporo, Japan. They use Yamaha Corporation's Vocaloid 2 singing synthesizing technology. Their voices are sampled by Asami Shimoda. They have performed at live concerts onstage as animated projections. Many songs have been created with them.

The characters' given names are derived from characters in Fist of the North Star, and the concept of 'right' and 'left', like on earphones. Their surnames came from the Japanese words for mirror and sound.