From the looks of it, this game isn't very kind to people unfamiliar with the Werewolf: The Apocalypse lore or setting.

If it helps:

Caern: A special location valued for its spiritual power. Can be small, like a single room of a house, or huge, like a full high-rise.
Garou: Werewolves. Similar to Kindred for Vampires, the word is only used by other Werewolves.
Endron: One of the many company branches of Pentex, which is a huge multinational conglomerate that serves the Wyrm's interests.
Wyrm: One of the three primal forces of the World of Darkness. The Destroyer. Driven mad by The Weaver, the Builder.
Lupus: The true wolf form, and also one of the states a Garou can be born in.
Black Spiral Dancers: Formerly the White Howlers, this tribe of Garou was corrupted by the Wyrm.
Frenzy: The loss of control and outpouring of Rage due to stimuli such as humiliation, seeing a packmate get hurt or killed, being attacked by Silver weapons, etc. and then failing a Frenzy check.

For the NPCs, I'm guessing most of them are Garou with a few Kinfolk (children of Garou who can, or maybe won't, become Garou) in there.

The rest is typical middle-market stuff. Cyanide does pretty well with that if the two Styx games are anything to go by, but for the moment, this is the best we can get with an IP this old.