Gerald Robotnik

The grandfather of Dr. Eggman and Maria Robotnik, introduced in Sonic Adventure 2. Noted as "one of the most brilliant minds of all time", Gerald is best known as the creator of Shadow the Hedgehog. His talents were, however, many and various; he also designed the Space Colony ARK, Biolizard, Artificial Chaos, the Eclipse Cannon, the Chaos Drives and had conducted research on Chaos Control.

(Source: Sonic Retro)