Daemonrealm is a mysterious plane from which all Demons come from supposedly come from. Since nobody has entered a portal to Daemorealm (or anybody who has has not returned) and no demons give descriptions of their homeplane, our knowledge of Daemonrealm exists from only educated hypothesis and the study of the demonic physiology.
From the demonic physiology, we can gather that Daemonrealm is very hot, as Demons are adapted to withstand heat. Demons have evolved to a canabilistic diet, so knowledge into the ecology of Daemonrealm is very limited. Since the plane has developed planar links with the Fire Realm, it can be assumed that it is a land of fire, ash and scorched earth.
Daemonrealm, as far as experts know, is inhabited purely by Demons and their wicked gods, of which we know only of one, Kativa . Any other inhabitants which may exist in the realm have not been discovered or documented by anyone from Ulvania and no demonic sources have been found pertaining to them.
See Kativa for more information
A Goddess of presumed demonic origin, which the demons of Daemonrealm are seen to worship. Actual information on Kativa is sketchy at best.