Nibiiro no Chameleon

During the Economic Bubble, everyone, men or women, young or old, lived in a world that was filled with frenzy. In the air where strength overruns weakness, there is a "woman" who tries to avenge her past. But, there's a twist with this "woman". One is that she was a cold killer. Second is that this "woman" is actually a man.

(Source: Kadokawa, translated)