Dr. Cranium is the great-great grandfather of Dr. Brain as seen in the Quest for Glory: Shadows of Darkness.
Behind the scenes[]
Although not seen during the Dr. Brain series, Dr. Cranium makes several references to his great-great grandson, including the fact that he would be the focus of a future Sierra On-line game, the Castle of Dr. Brain. The Quest for Glory: Shadows of Darkness Hintbook, confirms that Dr. Brain is his great-great grandson.