Marcus Chaney, from Martian Dreams
He used to work as an actuary for the firm of Dicker and Higgins, but then fate had him on the space cannon when it was launched. In Olympus, they thought he'd gone mad after using the Dream Machine, and chased him away. Chaney then took up camp in Hellas.
The Avatar found him there in Martian Dreams. Chaney was actually quite sane, and told why he had been banished, and since he didn't like it in Elysium, he'd moved to Hellas. He told the Avatar of how he'd found out that certain martian berries granted psychometric powers, allowing one to "talk" to objects to learn their history.
He also spoke of his experiences with the Dream Machine and the risks. He said that the others were trapped in nightmares, separated from their bodies, while martians had taken them over. He also revealed how to return to the real world by just talking to yourself. However, he felt that was useless anyway, since the machine in Olympus had been destroyed by the paranoid Jack Segal and the one in Hellas was in disrepair. He didn't know if Elysium had one, but then he had the idea to learn with psychometric powers, how to fix the one in Hellas.
In the end, he returned to Earth in the new capsule.