Hi and welcome here,
If you playing a Ranger : have you ever tried the skill Way of the Ranger? Combine this with splitting Arrows and Explosive arrows or if you want more time, use Stun Arrows (use it against Raze!).
Summon your Creature and try a Ghoulish Head for him (do Rush Attact and Fatality, nice in combination with a Ranger build, imo).
Upgrading Summon Ghost is also helpful because the Ghosst can heal you! Or put 1 or 2 points in Hide in Shadows + Healing ! (while you are hided you can use Healing without becoming back visible!) But a warning : using Hide in Shadows did not work while an enemie is attacking you with magic, arrows or melee, so first jump or run a bit away behind a wall or pillar and then use Hide in Shadows!
On both chambers (Raze Healing chamber and the other where his minions appear), you can find a Lever to INactivate them (set OFF) ! Best try first the chamber of Raze his minions. I put the Lever while I was Hided in Shadows!
In my case I had the feeling that Raze put back ON those Levers ! So be prepared.
Good luck !
