Haru is an apprentice Period serving the Arc End 8th Branch, an organization dedicated to combating Spirals – monstrous beings born from human isolation. As a Period, he wields magic to fight these creatures. After a devastating theft triggers economic collapse, Arc End headquarters abandons the 8th Branch, leaving only three Periods, including Haru. Forced to rebuild their division, he and his remaining comrades undertake quests and assignments.

His background involves adapting to sustain the abandoned branch, grappling with financial instability, and pursuing missions to restore its function. During these efforts, he forges alliances and rivalries, particularly with the antagonistic group Wiseman, whose actions repeatedly intersect with the branch's objectives.

Haru's development focuses on his persistent efforts to rebuild the division despite scarce resources and external opposition. His journey underscores teamwork and resilience as he collaborates with fellow Periods to overcome adversities stemming from Spirals and organizational setbacks. While the narrative does not depict significant personal transformation, it consistently highlights his role in maintaining the branch's operations amid recurring challenges.