The Sins of the Serpent

Cursed and exiled, Hirayama Sosuke is the only person who can free Zheng Zixin from his dark past. They must put aside their differences in order to uncover the Dark Court's schemes. The Sins of the Serpent is a standalone spin-off that follows Zixin and Sosuke's tumultuous adventures through the pixie nation, Iniguthia, as they navigate through their forbidden romance.

After Zixin's affairs with various men are brought to light, his parents arrange for him to marry an angel from Aeyaviel, Lindie. There's just one problem: Zixin hates her. His parents' expectations of producing an heir to carry on their family's legacy forces him to butt heads with his father, leading him to consider abdicating the throne to avoid marrying her. But tensions rise in the Dark Court, pressuring him to accept the marriage to protect Wuzhen.

When he receives a forged letter, he seizes the opportunity to find the person who would dare to forge the Emperor's seal. While he expects to find a worthy opponent, instead he finds himself trapped in a scheme concocted by a pair of infamous kitsune. And what awaits for him is a mysterious labyrinth with an appealing scent.

Guided by the kitsune, he finds his mate, Hirayama Sosuke, who has been cursed by the Seven Deadly Sins to live in exile for the remainder of his life. They struggle to accept each other, knowing they come from two different worlds. However, Zixin lends his help to the trio, settling for never seeing Sosuke again after they've foiled the Dark Court's plans. But first, he must break Sosuke's curse and the only way to break the spell is to hunt down every Sin, re-seal them in the hearts of the Seven Virtues, and kill them.