Tor was a Joe Kubert series, originally created in 1953 for the comic 1,000,000 Years Ago!, by St John Publications. Much of the DC series consists of reprints from that book, although there is some new material as well. The book debuted with the May/June 1975 issue.
Joe Kubert is shown introducing this debut tale, which consists largely of strips designed for a newspaper run, which never got picked up.
This is one of the series that I consider an attempt to reach the Conan the Barbarian market, though largely only because of the time the book was released. It deals with a caveman in prehistoric times, so lacks much of the fantasy stuff that defines Conan. As well, the name and appearance of the character cannot help but evoke Tarzan, which was also being published by DC at the time, often with covers by Kubert.
This first issue is basically an origin story. We meet Tor as an adult fighting a dinosaur, and then go into an extended flashback. Tor and his parents live in a cave, and are in conflict with the mountain people. Young Tor gets beaten up by a similarly aged boy from the mountain people, Kobar. His father starts instructing Tor on how to be a fighter, explaining that he must learn to defeat his enemies with physical force.
Later in the story Tor gets attacked by a big crocodile, and Kobar comes to his aid. Then Kobar almost drowns, and Tor saves him. Kobar insists that saving Tor makes the boy his slave, but Tor counters that in saving Kobar he earned the same debt, which cancel each other out. Kobar reluctantly goes along with this. As the story ends, Tor tells his father that violence is not always the only answer.
A text page at the end of the book gives a brief explanation of the earlier publication history of Tor. It's great when it comes to talking about 1,000,000 Years Ago, and how it fits into the genre of caveman movies, but doesn't provide very much information on the actual earlier series. A few pages of early Tor stories are shown, pages that will appear in reprints in the following issues of this book.