Sooyoung,Yul,Yoona and Taeyeon are heiresses of 4 gangs. 

Their fathers are the leaders of the units,Ace,Diamond,Heart and Club. Those four are under the MATRIX.

Sooyoung,the Diamond.

Yul,the heart.

Yoona,the club and Taeyeon,the Ace.

Their real selves are still hidden,but one thing is for sure. They are just half humans.

They fight with different creatures. Wolves,vampires,anacondas etc. Those beasts are half humans too,but some are not.

Some are still undiscovered. And that's why they're hunting. To examine the changes in their enemies. Inhalation,Yes,they even examine that. The air that the dead body breathe,etc. Because they think that wolves only live on forests,so if there's a suspicious kind of gas in his lungs,then something's happening.

Taeyeon is a strong girl,she trained her off since she was young. She doesnt want for other to know so she pretended to be a weak one. Her father is the second leader of Matrix,the main gang.

And Yuri...She's cold. But she's a ert. But someone's more y than her! Her knowledge about Science is undeniably amazing. Her father owns so many hospitals around the world and she's striving so hard to surpass his father in making medicines to cure other people.

Sooyoung,she eats a lot. Her father owns a lot of restaurants. She loves to eat. So what? She's still sl