Since the Underland is an underground world of darkness, light is essential for survival, teamwork, and livelihood. Without light, humans and other creatures struggle to see, making it a necessity for navigating their dangerous environment. The novel often equates light with life itself, reinforcing its symbolic importance: Gregor notes, “Light…life…the words were interchangeable to the humans down here” (185). The prophecy refers to light in a metaphorically crucial way, asking “WILL THE WARRIOR DRAIN YOUR LIGHT?” in reference to the white rat Bane (39). Vikus and Gregor interpret this question to mean that Bane’s death would extinguish his “light”—his life. Since light symbolizes life throughout the novel, the two concepts become interchangeable and essentially synonymous.

Beyond its metaphorical significance, light is a precious resource in the Underland. Any glowing object is treasured because it provides safety and direction. The Regalians rely heavily on torches and fire, while Gregor and his group depend on the light that fireflies emit to guide their journey. The absence of light creates a feeling of helplessness, as evident when Gregor first flees from the rats in total darkness. In such moments, light repeatedly proves synonymous with life since losing it leaves characters vulnerable.