Okay ~ This is not gonna be descriptive as I want it to be because I don't remember this manga so well. What I remember in this, supposedly a good and caring guy is actually a yandere. At first he appeared like knight in a shinning armor but the truth is he actually a manipulative and delusional jerk. He trick the heroine with message or key chain I don't remember. I'm sure there a key chain in it. You may look at him like he the hero of the manga but actually he the villain. I remember at the end of the manga, he dress up the heroine with very pretty dress then lock her up in a big glass box. She alive but lock up. Inside the glass box, she sat in very elegant and classy chair. If I'm not wrong, the guy have problem with his dead mother or lover, I don't remember, thinking the heroine can help him.

To be honest, I don't know if I describe the manga right. I barely remember it but I know the guy lock up the heroine in big glass box. Correct me if wrong. Thank for reading. ~

¤ I'm a female human that want to explore the universe so I can find another Earth. ¤
♢ I'm a female human that want to sleep underwater cuz I find it surprisingly calm ♢
% I'm a female human that want to become a scientist but I can't because I don't like math, add-math and physics. %
@ I'm also a female human that just to stay in my room and wasting my time with favourite anime and manga. @

I'm also a female human that obsess with reverse harem related.

Maybe 3rd one shot of this? Shinigami Doll 😀

Yes ~ This is the manga I looking for. Thanks for helping me.

¤ I'm a female human that want to explore the universe so I can find another Earth. ¤
♢ I'm a female human that want to sleep underwater cuz I find it surprisingly calm ♢
% I'm a female human that want to become a scientist but I can't because I don't like math, add-math and physics. %
@ I'm also a female human that just to stay in my room and wasting my time with favourite anime and manga. @

I'm also a female human that obsess with reverse harem related.