Chronoa/Chronology

Human-Monster Interaction
In the Dwelling of Spirits, Rimuru attempts to save Shizu's students by having each take in a superior spirit to aid in stabilizing their energy. At Chloe's turn, an irregularity occurs and the atmosphere suddenly becomes tense. A powerful spiritual body, which is actually Chloe's future self, appears and subsequently possesses young Chloe. As a side effect, her energy became stablized.

Hero Awakening
Granbell tricks Yuuki into unsealing adult Chloe's body contained within the ark. Following the single world theory, young Chloe disappears, causing everyone to temporarily forget about her until adult Chloe's existence slowly adjusts in the current timeline. After Hinata's death, her consciousness is taken in by Chloe, and through some spontaneous phenomenon, the two are sent back in time to 2,000 years ago. Treading the same path to the future they departed from, they befriend Luminous once again. When the topic of what Chloe's public name would be as a Hero (which she usually skipped in past timelines), for the first time under Hinata's suggestion, Chloe took on the name "Chronoa," as she didn't want her real name to spread to the public and risk attracting her friend Leon's interest, causing undesired revisions to the future. As a result of the naming, Hinata's Usurper was stripped from her and integrated with Chloe, with the additional effect of the negative feelings within Chloe acquiring sentience. Observing this, Hinata concludes that Chronoa is akin to a monster.

After Chloe's consciousness disappears and Hinata assumes control of her body, she struggles to hold back the raging Chronoa, who was held at bay by the now non-existent Chloe. Hinata fears that their plan will be ruined. Reaching the appointed time decided beforehand with Luminous, she hands the mysterious mask to Shizu and regretfully parts with her. In her last before losing consciousness inside the ark, Hinata thinks of the laid-back slime and cracks a smile, deciding to leave the rest to him.

Back to the present, Rimuru successfully placates the raging Chronoa and resolves the situation. Chronoa goes through an upgrade into a Manas, allowing her to better manage Chloe's abilities and switch out with her anytime.