The legendary killer 'Biguang' who died due to his organization's betrayal. Reincarnated in the body of police officer 'Kim Kyungsoo', he vows revenge against Hwaguksa, the killer organization that betrayed him. He is the reincarnation of the legendary December Biguang of Hwaguksa. He moves to take revenge on Yu Hwa, his enemy from his past life. He started as a patrol officer but was specially promoted to corporal after single-handedly wiping out a gang at a nightclub drug deal. Since reincarnating as Kim Kyungsoo, he displays combat power comparable to his past life as Biguang, thanks to Kyungsoo's well-trained body. Biguang even noted that with a bit more training in this body, he could surpass Yu Hwa. Upon waking up, he found himself reincarnated as Kim Kyungsoo, a patrol officer at Ilsan Police Station. {As Biguang, he was picked up by a shaman as a child and raised as a killer. He believed the promise of freedom after his final mission (wiping out the Truth Sect), but was betrayed and murdered. He appears to have been the most skilled among the 12 Months.} No one except Hong Jun knows he has reincarnated.

Real Name: Jo Kyunghee Age: 25 Nationality: Republic of Korea Affiliation: Gyeonggi Ilsan Police Station (Patrol Officer) Occupation: Police Officer She is the physically weakest among the patrol officers, but she is exceptionally brilliant, ranking 1st in written exams and interviews. Unlike the other two patrol officers, she has the grit to insist on staying in the police force. Furthermore, there are many mentions of her potential shining through while being trained by Kim Kyungsoo. She is quite pretty.

Real Name: Hong Jun Nationality: Republic of Korea Family: Hong Yeon (Daughter), Beodeul Affiliation and Rank: Commissioner of Gyeonggi West Provincial Police (Superintendent General) Occupation: Police Officer Maybe an 'ojicon' (attraction to older men) target? (?)

Real Name: Hwang Heejun Age: 25 Nationality: Republic of Korea Affiliation: Gyeonggi Ilsan Police Station (Patrol Officer → Corporal) Occupation: Police Officer A black belt in grappling-based martial arts like Judo and Jiu-Jitsu, but he is a total coward. He is definitely stronger than Lee Sunghyun.

Real Name: Lee Sunghyun Age: 25 Nationality: Republic of Korea Affiliation: Gyeonggi Ilsan Police Station (Patrol Officer → Corporal) Occupation: Police Officer Like Hwang Heejun, he is a black belt in grappling-based martial arts like Judo and Jiu-Jitsu, but he is a total coward. He is definitely weaker than Hwang Heejun.