Chuuya and Dazai are 2 partners in crime, They both 'hate' eachother but at the same time they both are the only one who can understand eachother and now very well, frenemies, Chuuya died while on a mission with Dazai due to Dazai's lack of care. After that incident Chuuya became a fallen angle or spirit, who can roam around any where it wants. Meanwhile Dazai thought it was his fault for chuuya dying and became insecure, sad, emotionless, stays alone 24-7. Chuuya has angry issues.