Miku is the main character in Project SEKAI. She is a female virtual singer known for her blue-green pigtail hairstyle. She can sing in a wide variety of genres with her cheerful and cute voice. Among virtual singers, her name is known throughout the world, and through many generations.

She lives in another world called Sekai, and appears in the real world, along with her fellow virtual singers, to consult people who have trouble understanding their true feelings.