Diver, from Martian Dreams
The Avatar found him in the Pumping Station in Martian Dreams. Diver spoke of how it was his job to maintain the pipework of the master pumping station, and explained exactly the steps that were needed to actually fill the channels with water (it involved the Lens Towers and pumping control). Diver however warned, that the controls were now behind a deadly steam leak and that his limits didn't allow him to go to the controls himself.
He also revealed the existence of a machine that could coat objects with a rubber-like sealant. Diver added that the sealant didn't have to be green, any color would do. This was later important for Chsheket's outer covering.