Spoilery speculation.
spoiler
We already know she's in this location with Allison and Gog per https://killsixbilliondemons.com/comic/wheel-smashing-lord-3-64/
And Cio, like White Chain, has been around for a very long time simply by virtue of being a devil. If the high-level angels are aware the universe is being reset by Zoss, surely devils are. Perhaps Cio played a big part long ago?
Also, White Chain has been going through her arc of growth, but Cio has not completed hers. I wonder if White Chain's arc is something like learning how to change. Whereas Cio's is...learning how to make something positive that sticks around. She built an empire on the backs of blood and tears and slaves. What if she could build a different sort of empire, one that embodies the ideals she's hoping Allison will deliver to her?
Also, I think it's still possible that my theory about the highest-tier angels and devils being a bit of yin/yang is relevant. White with a dot of black, black with a dot of white.
Angels can only speak truth, right? So they're not "naturals" at the red art of lying? But are great at martial arts and self-discipline?
So what about crazy-pants Metatron? Who speaks, thinking he's 100% truthful, and thus manifests the most powerful red art of lying of all? If an ANGEL is utterly convinced something is True, will it not come into being even if it's an utter lie?
And what about Himself, who seems voluntarily bound up in laws and rules and contracts to keep the devil chaos at bay? Why is the biggest agent of chaos totally into contracts and laws and order? There must be a benefit to it, right?
I think the ending of Cio's arc will have to do with her deciding to Be something that isn't chaos, that isn't Yab--and stick with it instead of changing form or running from it or looking for a hero to save her.
So we'll have White Chain with a bit of disorderly Change in her, and Cio with a bit of Order in her, and Allison being Allison to pull it all together.
Or, I wonder if Cio being a "fanfic writer" will give some insight into Metatron, who is basically Yisun's fanfic writer. Which might suggest White Chain could give insight into Himself.
I don't know if any of this will play out exactly like this, but the themes I'm seeing in the comic suggest at the very least these things are being played around with by Abbadon.
::: :::