Looking for oneshot

Hi, can anyone help me find the name of this oneshot smut manga? It was called something like 'the dark prince....' but I can't remember it or the original JP name, tried searching but no luck and getting a bit desperate.

It's a short and simple dub/non-con story. The plot involves depressed/overworked FL who dies and is isekai'd to the prince's world, cold tyrant ML type. She is asleep in his room chained up in lingerie. He's sitting/watching her until she wakes up, wants her to have his heir and tries to get her pregnant. Later on she remembers she died, and somehow he is also responsible for her death and bringing her here. He'd been watching her in her world through some orb thing and liked her dead eye expressions (?) He wants to be her reason for staying alive. The artist has done other yandere stories as well, the art-style is shoujo.

Please let me know if you have the name of this one!