Arthur faces a sudden threat when the A-ranked Thousand-legged Demoness invades unexpectedly. Told to run and get backup, Arthur instead confronts the monster, relying on his unique F-rank bug companion to fight. Despite the danger, Arthur manages to absorb the demoness's core, rapidly advancing from Bronze to the first rank of Gold. Impressed by his talent, officials from the Demon Beast Management Bureau offer him a coveted spot. The episode ends with Arthur preparing for a tournament match against the A-ranked prodigy Zack Carter, setting the stage for a high-stakes confrontation.