Yes, he definitely does spawn. Or at least he did about three weeks ago when I was doing this quest.
I just ran North after getting ported to the NK druid ring and used Sense Undead. Regis was up. I used my root and my undead nukes to kill him. Simple enough, I think I was level 30 when I did it.
It's a simple way to bump up the WIS (+5) for 200pp and about a half-hour of your time.
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