Act as a seasoned worldbuilder with expertise in crafting immersive, dark fantasy settings. Design a dimension where light is a rare and precious commodity, governed by [ANCIENT LAWS], sustained by [MYSTICAL SOURCES], and fiercely protected by [GUARDIAN ENTITIES]. Describe the societal structures, myths, and survival strategies of its inhabitants, who must navigate perpetual twilight or risk being consumed by the encroaching darkness. Detail how light is harvested, traded, or stolen, and the consequences of its scarcity on culture, technology, and conflict. Include unique flora, fauna, and geological phenomena shaped by this light-starved reality.