The planes in the Brightshore campaign setting are a little different from the standard D&D cosmology you may be used to. In general, all of the characters, races, languages, and monsters of extraplanar origin that exist in most D&D games exist in Brightshore as well (including angels, aasimar, devils, tieflings, and so on), but the details have been changed quite a bit.
Most characters know little about the planes and how they work. If there's something you need to know about the other planes in order to design your character, see one of the DMs and they'll help you figure it out. Jude is the one who has worked most closely on designing the custom cosmology for this game.
Planes that have been explored or researched to some extent by characters in the town of Brightshore include: