And there are still more characters to introduce from this issue! Next is Chuck Hardy In the Land beneath the Sea. Yes, it's a hollow world campaign, this time set under the South Pacific, and can only be reached when a volcano causes a fissure on the ocean floor to open. How the entire ocean doesn't start pouring into the hollow world and drown everyone there is never explained.
Although Mighty Man says he's the son of normal humans, he's close to the right size to be a moon giant (appearing in 2nd ed.).
(Scans courtesy of Digital Comic Museum)