"Seven Deadly Sins: Seven Days" is a spin-off manga set within the universe of "The Seven Deadly Sins." The story centers on the character of Zeldris, the younger brother of Meliodas and a former member of the Ten Commandments. The narrative unfolds over seven days, exploring Zeldris's internal conflict and his relationship with Gelda, a vampire princess.

The plot begins with Zeldris, who has been cursed by the Demon King to serve as his vessel, struggling to maintain his sense of self. Gelda, who has been imprisoned for centuries, is freed by Zeldris, reigniting their bond. Over the course of seven days, Zeldris grapples with his loyalty to the Demon King and his growing desire to protect Gelda and forge his own path. The story delves into themes of redemption, love, and the struggle against fate, as Zeldris attempts to reconcile his past actions with his present desires.

Key characters include Zeldris, portrayed as a complex figure torn between duty and personal freedom, and Gelda, whose resilience and compassion challenge Zeldris's worldview. The Demon King looms as a central antagonist, exerting control over Zeldris and serving as a symbol of the oppressive forces the characters must confront. The narrative is tightly focused, with the seven-day structure providing a sense of urgency and emotional weight to the events.

The manga expands on the lore of "The Seven Deadly Sins," offering deeper insight into Zeldris's character and his role within the broader conflict between demons, goddesses, and humans. It balances action with introspection, providing a compelling exploration of its protagonist's journey while maintaining ties to the larger series. The story's brevity and focused scope make it a concise yet impactful addition to the franchise.