Showaera

The story begins in 1989 in Tokyo, Japan. Ayumi, a 23-year-old girl, is the girlfriend of Takeshi, a handsome and authoritative yakuza gang member. They seem like a happy couple, but Ayumi has a dark side unknown to Takeshi.  
Ayumi is a talented and well-known psychopath and hitwoman in the underworld. She does her job very well, but her needy nature and love for Takeshi often disrupt her concentration and decision-making. Over time, Ayumi becomes increasingly obsessed with Takeshi and becomes more possessive and yandere. Takeshi, who is unaware of Ayumi"s dark side, continues to love her sincerely.