just to update the spawn location, pretty much any of those Feral dog creatures in the NE of zone outside city of course can spawn him. there are about 5 of them.
Seen him pop in 3 different spots from the feral grendlaens in the NE part of the outside yard. Very easy named for a Tier 4. He just makes you lose him as a target randomly during the fight. Bloodclaw Staff dropped 3 times, Bloodclaw Hide Spaulders twice, Had him drop Grandiose - Head, Wrist and Hands. No Stole after 5 or 6 kills.
I got him to spawn in place of a feral grendlaen roughly due east of the city, between the NE and SE sentry stones. I suspect the PH can be any of several grendlaen along the eastern part of the zone.