“Last One Standing: Royal Massacre” is a psychological horror/murder mystery visual novel that explores a different side of the classic no-escape storyline.

After being abducted by a mysterious man who provides no name beyond "the King of the Competition" before ordering them to serve as his Court — the participants in his Royal Competition of Death, a challenge in which they will be forced to murder each other until one remains — fifteen unconnected people must figure out how to not only avoid untimely demise, but uncover the details of their situation and the King's motivation. This proves to be a much more difficult task than anticipated as perspectives clash, rifts form, and caution morphs into secrecy, raising the question of who can safely be trusted within their shared goals.

[From Itch.io]