WN/Manas: Chronoa

Manas: Chronoa「 クロノア, Kuronoa」is the Manas born from all the negative emotions of Chloe O’Bell that was sealed inside of her using Infinite Prison of Hope King Sariel.

After Manas: Lucia erased Infinite Prison, Chronoa was freed, and Chloe, having become incredibly strong-willed compared to before, decided to completely accept Chronoa and thus they fused into the complete Chloe O’Bell.

Spirit of Time
Chronoa was formerly known as the Spirit of Time in the story. According to Ramiris, she was some kind of astral existence, that abandoned her flesh and lived as a mass of energy. Rather than a spirit, she radiated some form of soul energy. At that rate, she would've dissipated. To prevent her dissipation, she either needed something to bind her soul or to reincarnate into a body. Without a body, they’d need to create some system for keeping her here. Which isn't simple even for a high-level spirit.

It is probably she was something born in the future. Something that came from the future, and not a spirit. It is also possible that she possessed Chloe to give birth to herself. If she is born in the future, it'll cause many problems. The latest events show her to be the time-traveling soul of Chloe herself, hailing from an alternate timeline where controlled by Yuuki, she brought forth the end of the world and is currently trying to prevent it.

Appearance
She is a beautiful girl, with silver-black hair, and an oppressive aura that had the vitality unbefitting of a spirit.

Plot
Throughout the multiple time travels that Chloe executed, the uncountable failures and losses she faced accumulated as negative emotions inside her and warped her personality. However, Chloe had hope that one-day things will get better. And thus in a certain timeline, she attained Hope King Sariel. With her Infinite Prison now stronger than ever, she decided to do something unordinary and sealed all her negative emotions inside her heart, thus retaining her sanity as a 'pure-hearted' Chloe. But somehow, due to some reason, Chronoa escaped Chloe's body and when Rimuru was summoning spirits for the kids in Ramiris' Labyrinth, she appeared in front of the young Chloe. She flew towards Rimuru, kissed him, and giving a look of disappointment, turned to touch the young Chloe. When Ramiris sensed all of the 'evil' from her, she instinctively decided to kill her but was stopped by Rimuru in the middle. Thus Chronoa fused with young Chloe and stabilized her.

It is unknown exactly  'why' Chronoa was able to escape Chloe's body, but there are several hypotheses. One of which, is that, it's possible that Infinite Prison can only seal one individual at a time (there are no records of either Chloe or Rimuru using it on more than two people at once), thus when Chloe sealed Veldora and fell into a slumber, she couldn't hold Chronoa anymore and she was able to escape.

It is also unclear about what happened afterwards, but after adult Chloe woke up, some phenomenon caused young Chloe's existence to disappear and Chronoa was inside adult Chloe again. When young Chloe disappeared, it temporarily caused everyone to forget about her, until adult Chloe's existence slowly adjusted in her current timeline.

During the fight against Guy Crimson, Manas: Lucia appeared and, through the authority of Justice King Michael overall Angel Series abilities, used Regalia Dominion and ended up controlling the minds of Chloe, Velgrynd, and Velzado, who had Sariel, Raguel and Gabriel respectively. Seeing how perfect and compatible this Hero (Chloe)'s body was with the Seraphim energy, she decided to possess her and use her as a new vessel since Lucia's body was a mere corpse.

Due to poor life decisions, she wanted to erase Infinite Prison since she only wanted the perfect offense of Absolute Severance and perfect defense of Castle Guard, and thus released the dormant Chronoa for good. Under normal circumstances, it was possible for Chloe to be overwhelmed and dominated by the immense negativity of Chronoa, but because of how differently things turned out this time, Chloe's willpower had improved by leaps and bounds and thus she decided to accept Chronoa into herself; since Chronoa was Chloe herself.

Now with her original powers, plus the power of a Manas, Chloe was complete, and authority-wise was a superior existence than Lucia, who was only a Manas. She erased Lucia from within her and that was her end. Additionally, Hope King Sariel became embedded into her heart and dissolved, leaving all the abilities granted by Sariel as (some kind of) Chloe's own Intrinsic Skill. Naturally, her personality also became more sly and cunning compared to her previous 'pure' self.