The Aloof Man Said No, but the Stinky Ruffian Insisted on It.

[Two male protagonists + yandere] "Doctor Gu is really young and promising. He already has a girlfriend." Gu Yan: "No, you're too polite. It's better to see your father first before talking." That's because Gu Yan didn't see the darkness in Lu Chen's eyes. [Some content is more complicated, you know, so those are put in the comments]