Captain Blue Jr., also known as Junior, hailed from Movieland's Blue Town, a settlement honoring the superhero Captain Blue. He protected the town while yearning for the day Captain Blue would return and grant him a V-Watch, signifying his official role as Blue's successor. That hope shattered when Joe received the V-Watch instead, sparking intense jealousy in Junior. Despite this rivalry, Junior chose to become Joe's sidekick, lending his deep knowledge of Movieland. Captain Blue later offered Junior a V-Watch directly, but Junior declined. Instead, Captain Blue gifted him a case containing two specialized V-Yo-Yos enabling transformation. His transformation phrase was "Henshin a Yo-Yo Ball Baby!" or "Henshin a Yo-Yo Baby!". These yo-yos became the core of his combat style, granting him various yo-yo-based attacks, making him the franchise's youngest transformable hero. Junior's relationship with Joe evolved from jealousy into a collaborative partnership marked by mutual reliance. He frequently spotted dangers or strategic openings Joe missed due to distraction, like obvious traps set by villains such as Hulk Davidson, Charles III, and Gran Bruce. During a mission against the combined robot Grancharulk, Junior was trapped inside but resourcefully dismantled it by removing critical screws, securing victory. As the conflict against the alien Gedow organization escalated, Junior continued fighting alongside Joe and Silvia, defending Movieland against monsters corrupting films and altering their endings. In a pivotal battle, Junior performed a Heroic Sacrifice. This act deeply impacted Joe, triggering a state of Tranquil Fury that fueled a decisive counterattack against their enemies. Outside the main series, Captain Blue Jr. debuted as a playable character in *Viewtiful Joe: Red Hot Rumble*, based on the anime continuity. His characterization consistently emphasized admiration for heroic ideals, dedication to protecting others, and growth from envy to a valued team member.