Looking for manga with romance between a human and a genuine monster. Not the "pretty boy" type of monster you often find in romance manga, but a genuinely intimidating/scary monster. Can be yaoi, yuri, straight, whatever, so long as the monster is an actual monster.

Mahoutsukai no Yome?

And this seems to fit, though I have not read it: Niehime to Kemono no Ou

superior in this story the girl lead is the monster queen and the male lead is a hero who has sworn to kill the monster queen. She has her terrifying moments and can be absolutely brutal though the story is her progression as a person and how she gains empathy for humans.

"You cannot understand that which you do not know and that misunderstanding breeds hatred."
-a night of a thousand dreams

Kind of Kainushi Juujin to Pet Joshikousei... He CAN be scary/intimidating... sometimes. But mostly fluffy.

~4400 manga completed
~1700 ongoing...