1st Issue Special debuted with a March/April 1975 issue. A tryout series, more or less like Showcase, each feature would only appear in a single issue. The 1st Issue Special banner was cleverly designed to make it look like each issue was really the first of a new, ongoing series, rather than a series in and of itself. And that worked, at least for me at 9 and 10 years old. The two issues of this book that I bought I was certain were going to lead to more issues of the same character, but they never did.
Jack Kirby and Bruce Berry provide the first new series in this run, Atlas. The story is set in a mythic past, in the city of Hyssa. Atlas appears in the town, promoted as a strong man, and defeats those who challenge him.
He is far from friendly, and it becomes clear that he is not just an entertainer. He actively attacks a city noble, and seems to have some greater target in mind.
At a convenient moment, Atlas thinks back on his past. His parents, his entire people, were murdered or enslaved by the nobility of Hyssa. Atlas would have fallen victim to them as well, but he manifested a degree of strength far greater than any child should have, which allowed him to get away.
He meets Chagra, who was searching for the fabled Crystal Mountain, where Atlas and his people are from. The leader of the Crystal Mountain people possesses great powers, which are passed on when he dies. Chagra figures out that Atlas is now the leader of his people, even though there are none left, which explains his strength. We see that the two have spent many years travelling together, as Atlas grew up.
Chagra seems to have some shady goal, though, wanting to find the Crystal Mountain, although his reasons are not clear. As for Atlas, he gets to face the leader of Hyssa, the man who killed his parents so many years ago.
But that's it. Issue is over, story ends here. The final panel insists that there is much more to the saga, but no one picked up these threads for over thirty years, until James Robinson brought the character back in the pages of Superman.