Jun, the two-year-old younger brother of the protagonist, was born following their mother’s fatal childbirth. His arrival thrust his sister into dual roles as sibling and surrogate parent, fostering her frustration as caregiving duties restrict her social life.

His existence fuels the story’s central conflict: his sister’s initial resentment toward the burden he represents, even wishing for his disappearance. This tension propels the narrative when a supernatural entity presents her with dream-world alternatives to her strained reality.

Jun’s dreams intertwine narratively with his sister’s explorations of these fabricated realms. His naive, unfiltered perspective—contrasting her turmoil—shapes dream sequences that mirror their emotional divide.

The climax erupts as their dreams violently intersect, destabilizing both worlds and compelling them to confront the chaos. Their resolution underscores Jun’s passive yet pivotal role in his sister’s journey toward acceptance, though his character remains static, functioning primarily as a catalyst for her evolution.

No expanded media beyond the original work elaborates on his background or purpose.