He's suspicious and terribly obsessed. Seme is quite manipulative and he's clearly the one who screwed up the main character's whole life. Looks like it's going to be a pretty nerve-wracking series.
I read it knowing it was a tragedy tag. It was obvious that the end would break my heart. That's why I was avoiding the tag of tragedy. Damn, that was sad..
By the end of this manga, we'll probably all be crying and heartbroken. I don't want to see these two end badly. Both understand each other perfectly.