Gwendolyn here. This is my first report, and I wish it were under better circumstances. I took Guy out to gather and sell Mort Myre Fungus.
We managed to get 40 mushrooms for a total of 1,000 gold with no trouble. I left Guy outside Canifis while I went into town to find the herbalist. I found him easily enough, and sold him the fungus along with the nailbeast claws for an additional 1,150 gold. Along the way I encountered Half-Lycan Billy, who I had to strike a bargain with to get him to leave me alone.
Guy had arranged to buy a substantial amount of food and wine from his brother by ship. We headed north to the coast and paid for the shipment before returning through Mort Myre Swamp. Within Mort Myre we encounted two angry Gargoyles. They seemed unable to penetrate my armor, but Guy wasn't so lucky. With just two strikes, Guy was wounded severely. At that point, he seemed to undergo some kind of... metamorphosis. His blade became much larger and his eyes began to glow blue. I didn't see much more, as a blast of holy energy hit me then and I couldn't see for a moment.
He was nevertheless struck down, and my following brutal attack forced the gargoyle that had defeated him to retreat. At this point I picked him up and just ran for it. I lost the gargoyle in the mazes of the marsh, and ran him back to Burgh De Rott as fast as my legs could carry us, burned all the while by the holy energy leaking from his limp body
I summoned Alexis, who attempted to heal him, but his injuries were too severe, and he bled out on the spot.
Additional/Personal Notes
I think Guy may have been similar to Connor in some form.