a Japanese J-pop musician, singer and songwriter from Sapporo, Hokkaido. Kotoko began her singing career as a member of I've Sound in 2000, and was later signed to Rondorobe under Geneon from 2004 to 2010. Kotoko left Geneon in 2010, left I've Sound and signed to Warner Home Video in 2011. She composes and writes lyrics (for herself as well as other singers in I've Sound) for numerous other song collections. She has contributed songs to numerous anime and video games including Please Teacher!, Maria-sama ga Miteru, Hourglass of Summer, Hayate the Combat Butler, Kannazuki no Miko, Shakugan no Shana, BlazBlue: Calamity Trigger, To Love-Ru, Accel World, Phantasy Star Online and Argevollen, among others.