You meet her during the new events with Mai and Dea, which start when you talk with Lili after you have all requirements.
"Version 22.12.24 adds new events with Mai and Dea, which'll unlock their marriage. The events also introduces a new and unique monstergirl called Nessa.
The story starts when you talk with Lili in the castle of Aldlyn after you have all requirements:
- Dea's previous good path events. [Solo scene with Dea in the secret hot spring]
- Beach scene with Lili.
- Marriage system unlocked.
- Chiyo's events done to the point that Mozaik is living at the big farm in Central.
- First dialog with Akai at the work area near Aldlyn."