Units of Nations (G.U.N.), killed Maria as Shadow tried to protect her. Maria's death traumatized Shadow, who vowed to keep his promise to her that he would protect the world from danger. In Sonic Adventure 2, Gerald's grandson, Doctor Eggman, learns of Shadow and revives him as part of a plan to conquer the world and defeat Sonic the Hedgehog. Shadow agrees to help Eggman and frames Sonic for their evil deeds. However, Shadow eventually allies himself with Sonic to prevent the world's destruction after he remembers the promise he made to Maria. However, he is unable to handle the power of all seven Chaos Emeralds in a Super state as well as Sonic, and plummets to Earth from space after the final boss fight. Shadow is presumed deceased until Sonic Heroes; Rouge the Bat discovers him alive in Eggman's base during a search. He remembers nothing except his name and Maria's death, and teams up with Rouge and E-123 Omega to find Eggman and learn of his past. In Shadow the Hedgehog, Shadow, still experiencing amnesia, becomes caught in a three-way war between Eggman, G.U.N., and the Black Arms, an alien army led by Black Doom. Shadow can choose to help G.U.N., Sonic and his friends, Eggman, or the Black Arms. At the end of the game, Shadow recovers from his amnesia and learns the truth about his past, including that Gerald created him using Black Doom's blood and Black Doom uses that to control him, but Shadow stands up to him and ultimately defeats him. After the battle, Shadow chooses to put the past behind him and move on, and in Sonic the Hedgehog is depicted as having joined G.U.N. Reception and impact Shadow quickly proved popular among players of Sonic Adventure 2, contributing to his return in later games. Additionally, responses to his introduction were favorable; critics considered his levels in Sonic Adventure 2 among the game's highlights. GameSpot Shane Satterfield wrote Shadow's levels were exciting and helped preserve the general theme of Sonic games, and wished they had been more plentiful. Nintendo Life Mark Reece similarly felt Shadow's levels successfully adapted the Sonic formula to 3D. However, despite strong sales, the 2005 Shadow game received generally unfavorable reviews and, according to Official Nintendo Magazine Thomas East, tarnished the character's reputation. Reviews for Shadow the Hedgehog criticized numerous aspects of the character, such as his controls, use