I can enter the forest, I just don't know where I'm going exactly
Viewing post in Yorna: Monster Girl's Secret comments
I already described the way. Go to Ice Peaks zone, move through the first cave and into the open map with the healing statue. There's only one healing statue in the zone. Get inside the cave right beside it and that's it - talk with the non-moth girl and defeat her.
There are literally only 2 caves you can get into in this zone.