What is the story of these exorcists and goblins who defeat villains?

Name: Koo Hari (Dating Choi Kang-lim) Age: 12 Height: 153cm Weight: 45kg Weapon: Ghost Ball given by Shinbi Features: Strong and brave. Personality: Kind but can be scary.

Name: Lee Gaeun (Flirting with Ian) Age: 12 Height: 152cm Weight: 43kg Weapon: None Features: Very considerate Personality: Timid but kind.

Name: Leon Raymond (Flirting with Guest) Age: 12 Height: 167cm Weight: 52kg Weapon: Aegis Cards Features: Strong and powerful as an exorcist. Personality: Kind and takes good care of Guest.

Name: Choi Kang-lim (Dating Koo Hari) Age: 12 Height: 167cm Weight: 53kg Weapon: Sword Features: Very strong. Personality: Kind but cold; treats Hari very well.

Name: Kim Hyun-woo Age: 12 Height: 162cm Weight: 50kg Weapon: None Features: Exorcist H(?), (Not actually a real exorcist) Personality: Kind and easily frightened.

Name: Koo Doori (Koo Hari's younger brother) Age: 10 Height: 130cm Weight: 51kg Weapon: Ghost Ball given by Shinbi Features: A cute prankster who owns a Ghost Ball given by Shinbi. Personality: Kind and easily frightened.

Name: Ian (Flirting with Lee Gaeun) Age: (Over 100 years old) Height: 165cm Weight: 53kg Weapon: High speed, punches, kicks Features: A kind vampire Personality: Kind but slightly cold; treats Gaeun very well.

Name: Shinbi Age: (Slightly over 200 years old) Height: 90cm Weight: 30kg Weapon: Magic Bat Features: Strong because he is a goblin Personality: Kind but a prankster

Name: Geumbi Age: (Slightly over 200 years old) Height: 90cm Weight: 25kg Weapon: Magic Bat Features: Strong because she is a goblin Personality: Kind and loves pretty things