After defeating Ketheric Thorm, I went back to the incubation pods in the underground mind-flayer base, and they were all empty. Also, when I walked around the pods beforehand, I fought Ketheric. There was nothing indicating anyone was there. I only knew Zevlor was there because of Forums online, which I had to check because I couldn't find him anywhere. After I did go back, I activated the neutral device, and it said he was there, but then once I opened the pods, it said they were all empty. I just want to save the man!!
