The Bladder is the night watchman. Pang Guang is the word for bladder in Chinese. Pang is a vesseled space, a container. Guang is in a lot of GB points, and is an alternate name for GB-24 Sun and Moon. The character either means a person carrying a torch, or a person with their head on fire, in which case they may be a human torch. It is translated as light, radiance, brilliance, light bearer.
That is the Bladder: Pang, a vesseled space; Guang, light. It’s a night light. It’s the light in the darkness. It’s the stars in the sky. It’s the campfire in the dark. It’s all about light in winter.