Sphere of emanation
Spheres of emanation were the range at which it was possible to channel power from a deity. In the I.C.E. Age history, the concept of "local gods" was more prevalent, who had much more limited scope. Their power would be tied to a physical location or "holy site", and they would become weaker as they moved further away. In principle this was true of all "gods", even the Lords of Orhan, who would not be able to survive outside of the solar system. However, when such a local god was at the focus of their power, they would become very formidable. It would be very embarrassing to lose such a fight, so the Orhanians usually allowed local deities to rule their own domains with autonomy. In the Shadow World history this was a major factor in their distant relationship with the world, because coming down and directly interfering in affairs would upset ancient balances of power. The Charon gods were unable to do so wantonly, in practice, because the Orhan pantheon was much more powerful.
Holy sites were much like Essence focii, or "nodes", except that they were sentient with "pseudo-personalities." Thus, they would express ire at being tapped by those they found disagreeable, which was more or less the basis of Clerics. The sphere of a minor god might only be one mile, whereas others spanned the whole planet and beyond. That means if your power derived from a local god, and you were beyond their range, you would effectively be unable to cast spells based on channeling that power. Local gods would also be much more likely to notice inappropriate use of their power. They would be more likely to directly aid a follower, but said follower would be more vulnerable elsewhere. Avatars were considerably weakened if projected from the moons, but not if they traveled through a powerful gateway.
Behind the Scenes
The Graveyard might be a sphere of emanation, with Bandur Etrevion as an extremely powerful channel of The Unlife. This would explain why the Ice Room is a node, and why the forest never grew back after thousands of years. There was a modern example of the concept in Meyno's Shrine, which used messaging that implied it was a "greater essence focus", an archaic type of node. These effects were removed after Meyno was released, at which point the room was no longer a node. When a god was "dead" or "killed" in Shadow World, it meant that they were rendered unconscious. In other words, they were "permanently discorporate", possibly lingering as a node but with no conscious will. Some of the gods of the Black Hel, who were more like demi-gods or possibly even "Dark Spirits" of Orgiana, were banished to other planes of existence at the end of the Wars of Dominion. Others were "destroyed" as such or imprisoned within objects. It was possible in principle to imprison such gods within weapons.