Niki's manga / #2 or 3 couples - depends on the view(1)

Think it ended now. It got kinda boring. It's in the world where something like vampires live. These "vampires" don't have to eat if they don't want to. They just suck energy somehow. These "vampires" - Royals hunt... something like a fallen Royals (basically Royals energy crystals, or something like that, can be infected by the feeling of lost - they can "fall", or the crystal can be poisened. If it gets infected they turn into basically mindless creatures who attack everyting around them). Royals live in big houses with staff. One of the staff, Kyon, falls for the Royal, Lucaon. Lucaon doesn't like humans - cause past (parents dead cause on of their staff poisoned them). They start to have sex. Eventually Lucaon oppens up to him just to get poisoned by another staff in his "friend's" (another Royal's) house. + There's the thing with Kyon being the double agent (which he doesn't remember for some time cause Royals have superpowers.). Well Lucaon get's cured. They start a new relationship. 1 there are some other couples but Lucaon x Kyon are the main couple.