Unlike Ki who had her own Divine Domain as a deity, Foel was a pure mortal with no divinity nor connection to the divine spirit of any kind. So to take Foel into the Ouroboros' Divine Domain, MF needed to connect her soul directly to the spatial dimension that branched within her soul.
This process shouldn't be interrupted by any means or the soul of the tanomobi would get fragmented and at the worst scenario, death.
Because of this method, it would feel like Foel was inhibiting someone's miniature realm and left her original body in the real world. Hence, when MF took her to the isolated chamber on the underground.
When Foel opened her eyes, she was greeted with an elaborate garden that filled the whole Divine Domain with numerous kinds of heavenly flowers. Most of them were iridescent and luminescent, some were small, some were big, some had many petals, some had long skirts that jig.
"So we're on a date after all."
