The Book of Supernatural Beings once said that The Angels have been banished from The Earth; because The Elderly was scared of what The Earth's impurity would done to their precious generations. The Book said, too, about The Angels' ability; they can manage a very calming aura; their wings, once they were unfold, will literally blind everyone, unless the owner holds its power; they have a stunningly beautiful feature. 

That is, only the purest of The Angels' ability. 

While The Cherubs (or Cupids, rather) are not as powerful as The Angels kind and The Elders still let them wander around The Earth; because it is their job. The Cherubs have the same beautiful features but less powerful than The Angels; but still, you don't wanna mess with them, because they usually hang with The Fairies, which makes them a little naughty and loud enough. 

Jeon Wonwoo knows these things, rather, he had read all of the contents of The Book of Supernatural Beings; being the bookworm that he is. And since he was still a little child, his parents, even his friends' parents, have been telling him about it; 'story telling session!' he remembered when Mingyu used to call it that when they were young, and still close to each other. 

Jeon Wonwoo is a Death God, the only heir of his clan; Kim Mingyu is a Pure-Blooded Vampire; Choi Seungcheol is an Alpha Werewolf, who has lead his pack; Lee Chan is a rare case, a Shapeshifter, a Changeling, the last one. 

And their prey is just a single mysterious being : Yoon Jeonghan, a new student and An Unknown.