Good to hear from you again Kazuki! Thank you for playing, and for the feedback. I'm very happy to learn you are enjoying the concept!
Some quick help:
There is a hidden path in Act 3 that takes you under the northern mountains (so east of the ruins, and far north of Sowthin) that leads to a hermit herbalist. The entrance is right by a Skystone.
This must either be found by accident, or if you visit Droppre (Act 1 herbalist) while playing as Wrix, he gives you a hint; most often it is missed, so I'm working on more tips for the player.
Good luck!
p.s. I've just started playing Heart's Fallacy this week, and will let you know how it goes!