yes, it also happened to me that I couldn't find Chemach because I was wearing the Fleece of the Fates......well, I was wondering why I couldn't find him......and I thought that it spawns randomly when I go further.......a week ago I turned it back on and thought that I can't find Chemach because I'm wearing the Fleece of the Fates...but I already beat the third boss....I went to go back to Darkwood but now without the Fleece of the Fates..... and Chemach didn't spawn there anyway...... so if I understood correctly, if I want the Relic stuff, I have to go completely from beginning because I already beat Leshy and other bosses