Birth name Lin Peiyu. Lawyer working at Yang Qiujun's firm. A supposed suitor of Hu Xiaoman. In reality he is a serial killer targeting people who abused their family and children, and chose to woo Xiaoman because her father was a pedophile who sexually assaulted his childhood friend Thomas (Who died back in Season 1). He became a serial killer partly due to allegedly witnessing his father and mother killing each other during a fight when he was a young boy. He eventually managed to kill Hu Guangming, but loses his memory after Xiaoman knocks him out. Gao Jieyu restored his memories along with his childhood memories, and he realized to his horror that he was the one who killed his own father. He confesses that while his main reason for getting near Xiaoman was to kill her father, he fell in love with her and deep in his heart he actually wished Hu Guangming would never return so he would never have to kill him. Jieyu injected an allergic medication to his drip, giving him a seizure. Xiaoman silently watched without alerting the hospital staff, denying him the bell and refusing to press it as he died.

Fu Lelin's Brother. Wheelchair-bound due to his step-father "Big Little Eyes" physical abuse when he was still a child. Possibly due to Jieyu's manipulations he and his sister believed their sufferings were due to them having been kidnappers of their parents in their previous lives and now they are atoning for their past sins. He had actually been practicing to walk for months, and tried to protect Lelin by making a false confession that he murdered Rookie and Monkey for raping his sister. Held Jieyu hostage before being shot dead by Xiaoman.

Serial Killer, who was another victim and patient of Gao Jieyu. Wanyi's first victim had his eyes gouged out for alleged negligence in operating on her baby daughter years ago. The second victim had his fingers cut off for taking her money as a bribe without helping her during her lawsuits against the surgeons, and the third victim had his tongue cut off for alleged broken promises to do his best to save her child. The fourth target was initially believed to be her own husband, but was revealed to be Yang Qiujun, mother of Hu Xiaoman, the lawyer who defended her. When Yao Wanyi was caught, Gao Jieyu realized that she had outlived her usefulness and tried to force Xiaoman to kill Yao Wanyi, having hold Yang Qiujun hostage. Yao Wanyi never made it to her fourth victim (Jieyu did it instead), and was accidentally run over by a car on the final episode as she tried to flee from Xiaoman and Da Bao.

Gao Jieyu's and Hu Xiaoman's Professor back in University. Came up with a theory that serial killers act the way they are due to their own DNA. While Jieyu adored Fang Rongge and believed in his research, Xiaoman disagreed with that theory. In a past case, it was revealed that Xiaoman believed that Fang Rongge was the mastermind behind a serial killer who went about cutting off people's vital parts (Which is now emulated by Yao Wanyi). Fang Rongge remained silent during his trial and was released due to lack of evidence. Xiaoman decided to transfer his fingerprints to a knife on the dead serial killer's body, framing him for murder. He allegedly committed suicide by blowing up his own car while he was still inside, which devastated Jieyu and turning her onto the path of a vengeful serial killer. He was apparently revealed to be the true mastermind in the finale, having faked his own death and manipulated both Xiaoman and Jieyu to go at each other from afar. He currently resides in Korea as a criminal psychologist and Xiaoman escaped from the police force so she could meet up with him, in yet another cliffhanger ending.