From the introduction:
By the Gods is the roleplaying game of myth and legend. While most roleplaying games encourage you to play characters who are basically human with some aspects of heroism and aspirations to legendary status, By the Gods lets you play full-fledged gods and heroes in a setting which provides challenges of equally legendary status. This does not mean that they are any less human or rich in character. They have the same depth of personality and strengths and weaknesses of mortal characters, but amplified by their superhuman stats.
You might think of By the Gods as a superhero roleplaying game with a fantasy style setting. The powers which are available to characters far exceed what even the most magic-oriented games offer, but within the context of the game they make sense and may even be all that keeps the characters alive, since the challenges they face will be the most awesome foes of legend. The By the Gods rules are oriented towards the exploits of minor deities, demigods and heroes, but play on higher levels is certainly possible, as well as adaptation to unusual settings like gods in the modern world.
There are many realms of myth to play in. We've provided a map of the mythological world from the rocky mountains of Basilia to the island realm of Tabrobane. You will also find information in the appendices on several major pantheons, as well as adventure scenarios to play in those settings. Don't limit yourself to what's here in these rules, though. There are lots of great sourcebooks on mythology and the same basic paradigms of legendary adventure apply to many different settings and myth cycles.
User summary:
By the Gods began as a supplement for To Challenge Tomorrow, published originally as By the Gods (1986 Edition) and revised as By the Gods (1993 Edition). The "god-level" game rules continued to evolve and by 1998 they were considered standalone rules forming a distinct roleplaying game.
In 1998, the final public playtest version 3.1 of the rules was circulated on the (now defunct) Ragnarok Enterprises playtest site, available for download, use, and commentary by a restricted group of playtesters. The materials for the game were developed alongside an unpublished "7th edition" of Ysgarth and an unpublished revised version of Challengers, to which they bear some similarity (a standardized mechanics system was envisioned, but not fully developed).
The game was not subsequently published commercially.