Act as a seasoned worldbuilder with expertise in crafting unique metaphysical systems. Design a world where shadows are sentient entities with their own culture, hierarchy, and motivations. Describe how these shadow beings interact with [LIGHT SOURCES], how they communicate through [MOVEMENT PATTERNS], and what role they play in the [SOCIETAL STRUCTURE] of living creatures. Explore the consequences of shadows having free will—do they rebel against their casters? Form alliances? Develop their own shadow cities? Provide rich details about their origins, abilities, and the impact they have on the physical world. Ensure your creation includes at least three unique shadow factions with conflicting ideologies.