Jean Couillard, from Martian Dreams
In Martian Dreams, the Avatar first met Jean's brother, Legrand, who had been ordered by Jack Segal to guard the smashed-up Dream Machine. Legrand was highly upset and concerned over the fate of Jean, who had ventured into the Olympus mines for more ore, but had not yet returned. Legrande agreed to let the Avatar's group in to see the Dream Machine if they first searched for his brother in the mines.
The group indeed discovered Jean in the mines, on the verge of death, mortally wounded by Rockworms. Jean gave the Avatar his Masonic symbol to bring back as proof of what happened to him, as he spoke his final words: "...Legrand will need this, he is almost third degree... the worms... damn the worms... God take pity on my soul..."
When the Avatar's group returned to Legrand, he was grief-stricken, but managed to regain his composure, and allowed them in to see the Dream Machine as agreed.