Yoichi Tsuitenai, once dubbed Japan's unluckiest middle schooler, endured relentless misfortunes—botched confessions to crush Miyo Kireida via misplaced love letters, perpetual accidents, and social alienation. His tragic demise arrived when an alien spacecraft collided with him, yet his spirit merged with Lucky Man, a cosmic entity, birthing the dual-being Luckyman. Transformation hinges on consuming a rakkyo, a pickled garlic clove charged with cosmic energy, allowing him to shift between his hapless human self and the superhero form.

As Luckyman, he dons a crimson jumpsuit emblazoned with the kanji "大吉" (great luck), sports elongated earlobes, and bears a teacup on his forehead with a standing tea stalk (chabashira). His taller, luck-infused physique executes sluggish, unremarkable attacks—Lucky Punch, Lucky Kick, Lucky Beam—that inexplicably triumph through chaotic environmental interventions. These powers wane under cloud-obscured skies, severing his link to the Lucky Star and leaving him defenseless.

Yoichi’s psyche oscillates between resigned pessimism and Luckyman’s brash, boastful persona, which credits nonexistent strategies to random chance. He evades direct combat, deferring to allies like the effort-driven Doryokuman, while his lingering affection for Miyo falters through persistent comedic misfortunes.

Within the Best 16 Super Heroes, a coalition repelling alien invasions, Luckyman reluctantly leads alongside fame-hungry Superstarman, whose regenerative prowess contrasts his own chaos-dependent victories. Battles climax absurdly: foes felled by stray pebbles, storms quelling threats mid-fight.

The fusion’s drawbacks bind him to time-limited transformations and external luck symbols. Even as Luckyman, Yoichi’s human form suffers slapstick calamities, underscoring the tension between his identities. His journey grapples with self-acceptance amid the paradox of wielding capricious cosmic luck—a hero tethered to insecurities yet burdened by duty.