Yuki Shimazaki emerges desperately seeking answers about her missing brother Shogo Shimazaki, convinced an "angel" abducted him. Her initial state is one of profound distress and vulnerability, frequently overcome by tears due to Shogo's absence and her belief in supernatural forces.

Her path crosses with Kouki Maeno at the Tokyo Metropolitan Government Building, where he offers help finding Shogo. Their partnership in the search sparks a deepening mutual affection. Unbeknownst to Yuki initially, Shogo had transformed into an angel after Apos interfered; Shogo wielded his powers for vengeance before losing control, leading to his death at Rin Asougi's hands.

Following Shogo's death, Rin grants his Time Fruit to Kouki, who then gives it to Yuki. Yuki and Kouki later marry, resulting in her surname change to Maeno. They have one son, Teruki Maeno, born roughly twenty years after Shogo's demise.

Kouki ultimately dies after becoming an angel to rescue Rin and is subsequently killed by Apos. As a widow, Yuki raises Teruki alone as a single mother. She is characterized by a quiet, reserved demeanor, masking an underlying resilience forged through enduring personal tragedy.

Yuki lives long enough to witness Teruki reach adulthood but passes away before the birth or significant events involving her granddaughter, Mishio Maeno. Her legacy endures through the Maeno family line, carried on by Teruki and Mishio.