The quote reflects the idea of accepting the burdens of one's past as a part of life. The character has become so familiar with his old darkness that it feels like a companion, indicating a sense of resignation to the struggles he faces. Rather than resisting or fighting against it, he accommodates this darkness, suggesting a level of understanding or acceptance that comes with time.

This passage evokes the notion that everyone carries their own struggles, much like sharing space with others in a crowded environment. It highlights how people learn to live with their challenges, making room for them as a part of the human experience. This sense of coexistence with one's difficulties can lead to deeper insights and connections with others who share similar experiences.