Chloe Aubert began as a Summoned Otherworlder, transported alongside Leon Cromwell to the Cardinal World through dimensional distortion. Immediately separated from Leon by a 300-year temporal shift, this traumatic event potentially triggered her Unique Skill "Time Travel," born from survival instinct under extreme conditions. As an incomplete summon, her body struggled with magicule overload, leaving her with only years to live. She joined Class S at Freedom Academy in Ingracia Kingdom among five summoned children under Shizu Izawa's guardianship. Initially introverted and quiet, she possessed waist-length black hair, blue eyes, and favored reading picture books and manga. Her typical attire was a simple pink frock and black student cloak. Despite her stoic exterior, she displayed deep emotions and fierce loyalty to friends. After Shizu's departure and death, Rimuru Tempest became her mentor. During a visit to the Dwelling of the Elementals to stabilize the children's magicules, Chloe merged with her future self's spiritual body instead of absorbing a greater elemental. This resolved her magicule instability and granted fragmented memories of temporal cycles. Rimuru later entrusted her with Shizu's Anti-magic Mask and provided new attire crafted by Shuna. Her Unique Skill "Time Travel" activated involuntarily whenever Hinata Sakaguchi died near her, propelling her consciousness 2,000 years into the past. Accumulating memories across loops, she adopted the alias "Chronoa," the legendary Masked Hero. In this identity, she wore a white cape dress over a black shirt, black corset, gauntlet gloves, and ruby necklace, styling her hair in a side ponytail. As Chronoa, she confronted Veldora Tempest after a city's destruction. Temporarily guided by Hinata's consciousness, she imprisoned Veldora using the Unique Skill "Infinity Prison." Her abilities evolved into the Ultimate Skill "Lord of Space-Time (Yog-Sothoth)," enabling time stoppage. She later inherited "Sariel, Lord of Hope" from Granbell Rosso, though its life-death manipulation proved challenging. Her magicule levels rivaled supreme spirits, exceeding even "Great Sage's" analytical capacity. The loops entangled her in paradoxes: recurring timelines where Rimuru perished, the Jura Tempest Federation collapsed, and Veldora raged. She worked to prevent these outcomes while interacting with figures like Luminous Valentine and Leon Cromwell across centuries. A critical paradox involved Shizu's Anti-magic Mask: Rimuru gave it to Chloe, who later traveled to the past and gave it to Shizu, creating a closed loop. After numerous cycles, she returned to her original timeline, merging with Chronoa to become the "God of Space-Time," shattering the cycle. This stabilized her powers, enabling her to protect Rimuru from threats like Michael's parallel existence. Her relationships shaped her path. She developed profound affection for Rimuru, competing with friend Alice Rondo for his attention. She addressed him as "Professor," trusting him deeply and occasionally expressing feelings through bold gestures like kissing. Hinata's death remained pivotal to her time-travel trigger. Leon Cromwell stayed a cherished childhood friend, while Luminous Valentine aided her heroic endeavors. Post-loop resolution, she and Class S relocated to Tempest, participating in the Founding Festival and continuing their education.