"They can be placed at the corners of the tiles" should be "They are placed adjacent to the corner of one of more tiles." The example is very helpful.
Mining petrified demons: instead of a limited supply of green cubes, why not just add an extra dozen or so to the components of the game? Then you could delete the comment about using spare rotation tokens.
Rotate Trail Signs: can I only rotate a tile 90 degrees counterclockwise, or can I rotate it to any position?
Suggested edit: "If all Demons have been captured and there are none left in the Dark Realm, the game ends in victory!"
End Game Conditions - a Demon steps on the same tile twice - seems difficult to keep track of where the demons have been on a 5x5 board.
Consuming Growth scroll - Demons go into the supply instead of the quarry. Can they be mined? Can they only be mined if they are green?
Lightning Rod scroll: how do you mark 1, 2, and 3 charges? Does this negate terrain penalties for obelisks?