Love Prison: The Sadistic Knight and the Indecent Vow Series by Kei Shichiri

"Hey, what are you licking?!" As the tongue flicks its way across me, my body responds! Takanashi Yui was born into a family that people have an aversion to due to a curse that makes them all die early deaths. Then, one day, Yui's suddenly attacked by a monster!! Right at the last minute, a mysterious, beautiful boy saves her and suddenly gives her a deep kiss, which completely freezes her up... more"Hey, what are you licking?!" As the tongue flicks its way across me, my body responds! Takanashi Yui was born into a family that people have an aversion to due to a curse that makes them all die early deaths. Then, one day, Yui's suddenly attacked by a monster!! Right at the last minute, a mysterious, beautiful boy saves her and suddenly gives her a deep kiss, which completely freezes her up. Then, ears and a tail sprout from his body?! In order to use his strange powers to save Yui from the monsters, he needs energy from her body, and assaults her with sexy touches... What in the world's going to happen?! less

Yui lets her guardian beast Natsu kiss and fondle her body in order to break the curse... And as he does, she grows even more sensitive... Then one day, a strange man appears at school and confronts her with an arrogant attitude. Then, he even asks her to make a contract with him! How is this man related to Natsu?!

Natsu stopped touching me.I don't want any other man to touch me, but the gap between us keeps growing. Then one day, a cheerful male transfer student named Shiraha appears in school and acts friendly toward me. Then, he suddenly tells me I'm cute, and attacks me when we're alone?!"That loyal dog doesn't have what it takes to satisfy you, does he?" What could he mean?!

Akeno, the man responsible for the curse on the Takanashi family, captured Yui and plans to make her his! How will this romance between human and guardian beast end up?! It's finally come time to have a showdown with Akeno, the man who is responsible for everything! Yui's finally realized how she feels about Natsu... but how will their romance end up?! This is the raging conclusion to this modern fantasy!