An Embed is a rule or natural law already hard-coded into the workings of the world that a demon can tap for a specific effect. For a mundane example, consider a child who knows of a loose board in a neighbor’s fence. He can move the board, take a shortcut through the neighbor’s yard, and save himself the time of running around the block. Anyone could do that, provided they have the same knowledge the child does (that is, that the board is loose) and that they can fit through the opening thus created.