I have an idea of what's going on but will update you once I upload a new fixed version. The new version will have some sneak peak at the upcoming content as well.
I've uploaded a new build that fixes the Possession Training input and the sage quest line. Since this version has a sprinkle of v0.2 in it, the Sage quest line has been moved to trigger when you meet the new character. The note system also has been added in. Thanks again for playing!
If you do encounter more bugs do let me know and I'll have those patched up for the new update.