Zeldris, the Demon King’s second son and Meliodas’s younger brother, emerges as a complex fixture within the Demon Clan, shifting from secondary antagonist to deuteragonist. Trained by Cusack and Meliodas, he honed formidable physical and magical strength, once idolizing his elder brother until Meliodas’s abandonment for Elizabeth fractured their bond, leaving resentment in its wake.

Tasked with annihilating the Vampire Clan during the Holy War, Zeldris defied orders by sealing his lover Gelda—an act of rebellion betraying a hidden tenderness beneath his loyalty to clan duty. As the Ten Commandments’ leader, he enforced his father’s edicts mercilessly, driven partly by a clandestine hope to resurrect Gelda, believing her lost.

After the Demon King’s fall, Zeldris ascended to lead the Demon Clan. In *Cursed by Light*, his reluctant reconciliation with Meliodas unfolds through tense cooperation, their rivalry easing into pragmatic alliances. Sibling disputes settle via playful rock-paper-scissors clashes, while joint battles against Dahlia, Dubs, and the Supreme Deity reveal lingering mutual respect. Gelda’s influence softens his stern demeanor, unveiling dry humor and romantic devotion.

His combat prowess blends darkness-manipulation magic, peerless speed, and the vortex-generating *Ominous Nebula*. Though initially overestimated against the Demon King, his strategic brilliance and raw power prove critical in toppling the Supreme Deity alongside Meliodas.

Centuries later in *Four Knights of the Apocalypse*, Zeldris governs the stabilized Demon Realm, his arc concluding as a ruler balancing authority with hard-worn wisdom. His journey—from vengeance-driven warrior to a leader prioritizing peace—mirrors a redemption anchored in love for Gelda and acceptance of his brother’s path, cementing his evolution into a figure of tempered resolve.