Not much has been known about Yasu’s life before Control's Book, however it has been confirmed that he lived with his parents Daku and Keiko, and had a group of friends that went missing. (Chapter 1-4) Kusonoki is Yasu's great x10 grandfather from the Edo period. A young man named Yasu went to his old high school in search of his missing friends. Yasu was born on September 4th, 2000. He is 20.