My billionaire roommate is the Demon King

Unemployed painter Emma thinks she struck gold when her drop-dead gorgeous new roommate pays a full year of rent upfront—demanding only that she never ask about his past or open his door. But when strange events expose him as a 900-year-old Demon King disguised as a billionaire CEO, an accident binds their souls in an unbreakable contract. Forced into a fake relationship, their staged romance sparks real feelings—just as Emma discovers her own origins are far more astonishing than the demon sharing her home.