Grell and Colletta deliver another excellent story, divided into two parallel tales, in Warlord 17 (Jan 79).
Travis Morgan and Tara are continuing on the hunt for their son, and wind up crossing a vast desert. In the middle of it they come across an abandoned city, which Tara recognizes as Timgad, the city of evil magicians. They are desperate for water, so against Tara's advice Morgan decides they need to stop there and find water. At this point, a second tale begins, running along the bottom of the pages. It follows a tiny wizard, Ogir Falconeye, who came to Timgad many years before.
The two stories parallel each other. Morgan and Tara find water, but wind up attacked by nasty creatures, and in fighting them Morgan falls into a dark chamber. Ogir retrieves a cask with a magic gem, but also winds up falling into the same chamber. Morgan winds up finding the same cask Ogir dropped.
In the chamber both men, at different times, have to face an amorphous monster, which they are unable to make contact with, although it can kill them. Morgan sees a skeleton on the floor, in a mystic symbol, which we then see Ogir draw.
Morgan realizes the runes on the symbol match those on the cask. He takes the glowing green gem from inside it, and uses it to defeat the monster. We also see that Ogir winds up trapped in his symbol, and becomes the skeleton that Morgan saw. Morgan keeps the gem, hoping its power will aid him against Deimos.