Arthur is initially successful, but Cusack reveals that Arthur's body is physically unable to handle the immense weight and power of Excalibur, causing the heroes' souls within the sword to tremble in fear.
Following the tragedy in Camelot, the surviving forces begin preparing for the inevitable conflict against the Demon King. Nanatsu no Taizai: Kamigami no Gekirin Episode 21
Tasked with invading Meliodas' lair to stop him from becoming the next Demon King. Meliodas and the Ten Commandments Arthur is initially successful, but Cusack reveals that
Cusack uses his "Resonant" ability to manipulate Arthur, forcing the young king to stab himself in the heart with Excalibur. Despite Merlin’s desperate arrival and attempt to shield him with an ice spell, Arthur ultimately dies, lamenting that he failed to meet Merlin’s expectations. Merlin's Grief and Backstory Arthur is initially successful
