- Flat Earth setting: sea spills off the edge to infinity
- Centre of realm is north
- Swords and Sorcery: races of humanity; no fantasy races (elves, hobbits, etc.)
- Sun is a red giant, old and bloated; it never rises to a zenith; rather, it skirts the horizon
- Two moon: both oblong; one larger and slower to revolve; one smaller and quick to revolve
- The Green Death wiped out most of humanity about 1,000 years ago
HYPERBOREA- A Role-Playing Game of Swords, Sorcery, and Weird Science-Fantasy