i wanna say his place holders are sand giants in the zone and possibly some others? im not 100% but i do remember killing sand giants to get him to spawn and eventually that worked for me.
https://wiki.project1999.com/An_anci...s_(Southern_Ro)
looks like i was half right, hes on the same spawn cycle as the AC on sro, so killing any of the placeholders for that mob can also spawn him.
gl to you on yer ro boots!