Rengoku Kitan: S-kei Kishi to Inmitsu no Chikai

"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?!