Yes, there's a skull just next to the book of death in Death Valley, he'll give you a quest to collect his bones strewn around Necrocom castle (mostly), and on finishing the quest, he'll go back to the Great Forest, again next to the book, where he'll sell some level 5 units. In my case, it was mostly cyclops.

Are you telling me that quest is always there and I've only seen it once in my 8 games? That's not very observant of me.

Thanks guys.

Yep it is always there.