The Billionaire's Kept Woman - Chapter 395 - Death Row

One day, Luo Jian woke up from his sleep and found himself in a locked chamber where the door and window were all sealed. A note with a few lines written on it was tacked to the wall: “Escape from this room within an hour, otherwise, you will die.”

There is a sequel called Reincarnation Night (轮回之夜) that takes place in the same universe but has different main characters

- Description from Novelupdates

Lucifer, an ordinary orphan boy who was brought up by a wealthy family to be the playmate of their daughter.That's how things have been until one night, when he got attack by something unnatural, that was the night the world changed for him.p.sThis world is going to be dark, lots of killings, a lot of r18 contents, most not even involving the MC, also Mc is not going to take all the girls he comes across, he will have female friends he will make along the way, there will be Yuri contents and lots more, but Actions prevails them all.

Side story of Kyoukai Senjou no Horizon bundled with the first press release of the 1st, 3rd, 5th and 7th Blu-ray volumes of both seasons of anime.

This side story follows Asama, Kimi and Mitotsudaira aboard Musashi one year before the beginning of the main story, as Asama is considering to create a music band together with her two friends for the next festival in Aki, a territory under the governance of K.P.A. Italia.

I met the male lead in prison.