Dev log from Dec 18.
"In the next build, there will be a small part of content about H-Demon, the strongest boss in the game, the cause of everything. So now is a good time to improve things with her.
Her old model doesn't match the theme compared to other models, so i changed her with the new model, you can see in the photo above. Now, she will be the same model type as the H-Goddess.
I'm trying to finish the Dungeon 3 as quickly as possible, it's a big dungeon with new enemy system and gameplay so it will take a lot of time. Hope you can wait!"
amfor I guess the most accurate answer is "soon"
Also, it looks like dungeon 3 is the underwater/aquatic dungeon (
because apparently underwater levels are mandatory.....)