Kaede Yuuki, Hiroshi Yuuki's younger sister, once idolized her older brother with immense pride. She frequently boasted to friends about his athletic promise on the junior high and early high school track team, inspired by his seemingly bright future.

Their relationship fractured after Hiroshi suffered a traumatic failure during a high school meet, publicly tripping and wet himself, leading to intense ridicule. Kaede's attempt to comfort him backfired, causing Hiroshi to abandon track completely. He retreated into a NEET lifestyle centered on loud, intense VRMMO gaming sessions, keeping irregular hours.

Disappointed by his surrender after one failure and his withdrawal into gaming, Kaede reacted with scorn and verbal abuse. She openly labels him "lame," expresses disdain for his choices, and belittles him, creating hostile interactions. Underneath this frustration, however, Kaede still yearns for Hiroshi to become the "cool big brother" she admired. Their mother observes that Kaede's harshness may stem from this unmet expectation.

As Hiroshi starts taking the VRMMO Kiwame Quest seriously, demonstrating real effort and experimentation both in-game and in his daily life, Kaede's attitude begins to change. She gradually resumes offering him support, signaling tentative reconciliation and an improving sibling bond.

Kaede possesses medium-length brown hair and yellow eyes. She typically wears a standard brown female school uniform. Her demeanor reflects her internal conflict, often appearing cold or verbally aggressive towards Hiroshi, though noted tsundere tendencies hint at lingering care beneath her harsh exterior.