Blood River

Once outcast children taken in together by Blood River, Su Mu Yu and Su Chang He grew up as inseparable sworn brothers, sharing near-total trust. As Su Chang He's methods grow more ruthless in his push to reform Blood River, their diverging visions strain the bond, but the underlying loyalty between them never fully breaks.

Bai He Huai, the Miracle Physician, becomes Su Mu Yu's love interest and one of his few connections to a life outside Blood River. She is later presumed dead and secretly kept hidden from him for years, and their eventual reunion closes out the drama's central romance.

Su Zhe, the former holder of the "Kui" codename, mentors Su Mu Yu as an elder of the Su family. He fights alongside him during the succession crisis and transfers part of his own qi to save Su Mu Yu after a near-fatal battle.

Mu Qing Yang and Mu Xue Wei are a romantically paired couple within the Mu family, described by fans as the drama's official couple pairing. Facing a losing battle, Mu Qing Yang confesses his feelings and speaks of their wedding plans before the two make a final stand together and die side by side.

Su Zhe is Bai He Huai's father. Their relationship connects the Su family and the Baihe Medicine Hall storylines, and his fate is tied emotionally to hers as her presumed death and eventual survival play out.

Mu Yu Mo and Tang Lian Yue share deep unresolved feelings for one another, but the demands of duty, especially his rise to head of the Tang Clan, keep them apart. Sources differ on whether the pair reconcile or remain permanently separated by the story's end.

Su Yun Xiu serves as the martial arts master to both Su Mu Yu and Su Chang He. Her guidance shapes their combat skill, and she later makes a unilateral decision affecting Su Mu Yu's personal life by concealing Bai He Huai's survival from him.

As Patriarch, Mu Ming Ce broke Blood River's founding law to spare Su Mu Yu and Su Chang He after their act of defiance, recognizing their extraordinary talent. This act of mercy shapes both young men's rise within the organization and underlies their later loyalty to his memory.

Mu Ming Ce also spared Su Chang He alongside Su Mu Yu, integrating him into the Su family and setting up his eventual rise to head of the Su family after the Patriarch's death.

As Head of the Mu family, Mu Zi Zhe competes with Su Chang He and other clan leaders for the vacant Patriarch seat after Mu Ming Ce's poisoning, dispatching assassins in the ensuing power struggle. Their rivalry is part of the wider three-clan succession conflict that drives the plot.

Crown Prince Xiao Yong is assassinated on Su Chang He's orders as Blood River becomes entangled in court politics. The act is a turning point that alienates Su Mu Yu and fractures the brotherhood between the two leads.

Prince Langya allies with Su Mu Yu and Su Chang He, offering support to help Blood River move out of the shadows and toward legitimacy. Their alliance eventually diverges by the finale over differing values, though it began from mutual necessity.

Su Yun Xiu is master to Su Chang He as well as Su Mu Yu, tying her role into both leads' training and backstory.

Prince Langya's alliance extends to Su Chang He as well, as the two work together within the Other Shore plan to legitimize Blood River, though their partnership is ultimately strained by diverging values.

Li Han Yi has little patience for the imperial court's scheming, and this comes to a head when she uncovers Xiao Yong's secret poisoning of his own brother, Prince Langya. She opposes him directly, fighting his forces to protect Langya.

After Zhao Yu Zhen's death sends Li Han Yi into a demonic-influenced grief spiral, Xie Xuan helps rescue her and dispel the affliction, allowing her to return to Snow Moon City for seclusion. The two are also noted to be relaxed and amusing together during a separate stretch guarding Prince Langya in Tianqi City.

Ye Ya captures Mu Xue Wei and strips her of her poison for use in her own experiments, placing the two in direct, hostile opposition.

Ye Ya controls Tang Ling Huang, Tang Lian Yue's senior, as a drugged puppet and deploys him as a weapon against Tang Lian Yue and his allies, putting her and Tang Lian Yue in direct conflict.

As Left Shadow Guard Commander of the Shadow Sect, Luo Tian Xiang stands on the opposing side from Blood River and Su Mu Yu within the story's political conflict.

Li Han Yi and Su Chang He cross paths in Tianqi City while both are there watching over Prince Langya. She notes his growing strength with a mix of wariness and respect, and the two share a mutual acknowledgment that they might spar again someday.