Little to nothing is known about the Jam. These unknowns have the tendancy to appear and disappear at whim. Furthermore, there is no reliable data on what these entities are capable of as the constantly show new abilites and better manueverability and speed.
Faery is an alien world that exists on the other side of a large nail shaped funnel portal, located in Antartica. The anime depicts this world as being a craggy/Earth like world with less gravity and a vivid green sky. There are ruins scattered about as well as numerous canyons and rock formations.
JAM TYPE 1
JAM TYPE 2
I know these aren't exactly accurate, but then again, they were tough to begin with. I see so many of the human forces being built, but not a single Jam.
You better watch out all you Yukikaze fans out there. The Jam are coming for you!