I don't really remember the story or the mangaka, the only clue I have is that the manga (or at least part of it) is narrated with these Shakespear's lines:

Doubt thou the stars are fire;
Doubt that the sun doth move;
Doubt truth to be a liar;
But never doubt I love.

If you know its name please help me out! Thanks a bunch 🙂

Was it definitely an original story or could it be a doujinshi?

I don't remember that either. But I think it's an original one, since I don't read dj very often

Oh I see, I think that Kuroshitsuji's Phobia dj had that quote but that's probably not it then.