fight of a fallen angel

Tobi manes a boy who lived a relatively normal life among other humans.
It wasn't until he bumped into the devilishly adorable fallen angel, carina halls, that his life finally began to make sense.
However, carina proved to be tiny and seemed to have an unhealthy obsession with human things. Tobi soon learnt that carina had taken an oath never to kiss a human being.
When Tobi's daring sister is injured in a demon attack accident, Tobi realizes his own life is at risk.
Despite carina's blue and grey eyes and bloody wounds, Tobi finds himself falling for the fallen angel. Only fate will decided whether he kills or protects him.
Will Tobi find it in himself to kill the only creature who has ever made him feel truly on edge?