I think it was a QT story The FL was transferred to this new world and because of a complication or something, her soul was in a man's body. The settings for this story arc is a prison, and the ML was the strongest in this prison, and he takes the FL as his younger brother. The FL was sent in by the police to get close to the ML, but she forgets about that anyway. The FL was just framed to go inside jail I think? Or was she helping in a fight? And the person who died was from a wealthy family, so she became a scapegoat. The ML had a younger sister whom he adopted and that was where the FL was supposed to go. I remember that there was an initiation scene I think, where new recruits are bullied by a group of strong people in prison? I think the prisoners were classified by letters. Then the FL beat up the leader of this group. This arc had a BE, the FL died all beaten up, then she wrote a message to the ML using her blood, and when the ML found her she was dead already. I hope someone knows this story, thanks a lot!
I think might be “The Villain Has Blackened Again” World 5, all I know is it had a gender bender arc and involves the mc in prison or something