Disagreeing with your phased comments. I located him very first day; he was just completely unreachable to me.
Agree withphased comment, every time I get close he phases out, reappears once I move away
He is technically in the four winds region do once you cross over to eternal blossom you can no longer see him if you have a pet go to a ledge south of him send you per to go attack him and then bring him to you being very carful to not cross over to the vale of eternal blossom. If you do that he will reset and disappear