Shadow is the Ultament Lifeform created by Dr. Robotnik's grandfather on the space colony ARK. He lives with the unforgetable, yet confusing, memory of Maria's death. Maria was like a sister to Shadow and he was hurt badly by her death. His promise to Maria was to give the people of Mobius a chance to be happy. At first he thought she wanted revenge, so he planned to destroy Mobius. But after Amy made him relise what her true wish was he kept his promise, by giving his life to save the world. Though many believe he survived.