E-103 Delta is one of Dr. Eggman's E-100 models, created immediately after E-102 Gamma. It looks identical to the other E-100's in structure, identifiable by its blue paintjob and the serial number on the right side of its torso. It has a cannon on both arms that fire homing missiles and hover jets similar to Gamma's. It was assigned to the Egg Carrier and ordered by Eggman to find a mutant frog that had swallowed a Chaos Emerald. It failed its task and was banished to the Mystic Ruins. After Gamma betrayed Eggman and abandoned the doctor, he encountered Delta in Windy Valley and the two robots fought. Delta was no match for Gamma and was destroyed, releasing the bird within its body that served as an organic battery.