Shadow the Hedgehog is an anthropomorphic black and red hedgehog, and a former adversary of Sonic the Hedgehog turned rival.
In the past, Shadow tried to destroy Sonic the Hedgehog as well as an entire planet. This incident involved the Space Colony ARK, in which Dr. Eggman used its Eclipse Cannon to blow up a part of the moon in order to show the world the power that he wielded. These events lead to Shadow teaming up with Sonic, Miles "Tails" Prower, Knuckles the Echidna, Rouge the Bat, and even Dr. Eggman himself to save the world. (StH: #5, #6)
Soon after, when the Black Arms invaded the world, Shadow once again teamed up with Sonic and Eggman in order to defeat them. Eventually, Shadow was forgiven for his crimes, and now actively seeks to protect the world. (StH: #6)
In the aftermath of the war, Dr. Eggman disappeared. Shadow began searching for the doctor in order to eliminate him before he could launch a counterattack. Eventually, Rouge the Bat helped Shadow by leading him to Eggman, but was secretly attempting to ensure that Sonic would reach Eggman first in order to stop Shadow. About a month after the end of the war, he and Rouge successfully reached Windmill Village where they found a seemingly amnesiac Eggman dealing with Sonic and the Chaotix of the Chaotix Detective Agency. After the doctor mentioned Eggman Land, the Shadow and Rouge revealed their presence and Shadow prepared to destroy Eggman. Sonic tried to convince them that Dr. Eggman totally lost his memory, even if he just mentioned his personal theme park, but was unsuccessful in getting through to Shadow. The two hedgehogs started battling each other, and during the fight, Sonic told Shadow that Eggman had helped them to save the world two times already. Still not convinced, Shadow asked Sonic if he had forgotten that Eggman attempted to eliminate him, but when Sonic told Shadow that he himself had tried to destroy him and a planet once and was forgiven, Shadow decided to give Eggman a chance to explain himself. Eventually, "Mr. Tinker" showed them Eggman Land, a tiny amusement park still not completed. With this, Shadow begrudgingly agreed not to harm the doctor, and he and Rouge went on their way. (StH: #5, #6)
The Battle for Angel Island
Eventually, Shadow was called to Resistance HQ. There, he and the Resistance's other allies were informed of what Sonic and Silver the Hedgehog had discovered in an Eggman base. As Neo Metal Sonic had conquered Angel Island and turned it into a flying fortress as well as secured the Master Emerald for himself, Amy laid out a plan on how they could liberate the island. Tails discouraged Blaze the Cat from going after Neo as Burning Blaze, as he believed that Neo could just copy Blaze's powers and become an even greater threat during their confrontation. Shadow was then assigned to help two of the assembled group's factions with breaking the Egg Fleet's control over Angel Island while Sonic and Knuckles the Echidna confronted Neo Metal Sonic. (StH: #9)
While heading for Angel Island in a Resistance Battleship, Rouge asked Shadow why he was going along with the team-up plan, to which Shadow replied that he was there for his own reasons. When the ship approached Angel Island, the Egg Fleet shot it down. By the time everyone had evacuated the ship and made it to Angel Island though, Shadow had already left the group to do his own thing. (StH: #9)
Shadow later made his appearance inside Neo Metal Sonic's stronghold on Angel Island where he encountered Neo metal Sonic's transformation, Super Neo Metal Sonic, who had Sonic and Knuckles at his mercy. Shadow attacked Super Neo Metal Sonic with a Chaos Spear through his torso, which forced him to revert back to his previous form as Neo Metal Sonic. Shadow then followed up by physically attacking Neo Metal Sonic until he was held back by Sonic, who was concerned that Neo Metal Sonic would copy his bio-data. Unfortunately, Neo Metal Sonic revealed that Eggman had removed the limitation that kept him from achieving his final form, and that to achieve his full power all he needed was Sonic and Shadow's bio-data in addition to the Master Emerald's power. As Neo Metal Sonic grew in power, Shadow and Knuckles tried in vain to attack him. However, Shadow, Sonic, and Knuckles were forced to evacuate the stronghold once the structure started to fold into Neo Metal Sonic. The ground soon after began to rumble and Knuckles noted that the Master Emerald had been cut off from Angel Island, meaning that the island would fall. Neo Metal Sonic then changed into a new form called Master Overlord and demanded that Sonic bow to him. (StH: #9, #10)
After fighting with Master Overlord, the giant robot grabbed Shadow, Sonic, and Knuckles and flew away from the island as he wanted them to see him destroy their allies, who were onboard an Egg Fleet battleship. It was then that Sonic came up with a plan. If they could get Master Overlord closer to Angel Island and take the Master Emerald from him, they could deprive him of his power source and save the island. When the three finally escaped Master Overlord's grasp, Shadow and Sonic focused on attacking his wings while Knuckles went for the Master Emerald. Soon after, Shadow was joined in his efforts by the rest of his allies, and together they forced Master Overlord back towards the island. During the battle, Shadow got shaken off Master Overlord, but was rescued by Silver with his psychokinesis. Knuckles subsequently got the Master Emerald away from Master Overlord and brought it back to Angel Island, bringing the island back to the sky while Master Overlord powered down to normal. With the battle over, Shadow was brought down on Angel Island where he then took his leave. (StH: #11)
Best summarized as a grim anti-hero, Shadow has a strong sense of purpose, practically to the point of stubbornness, and pursues his goals by any means necessary with a willingness to do whatever it takes to get what he wants, being willing to go as far as to take another person's life to ensure others' safety. This natural vehemence tends to make him launch himself into situations without fully thinking them through.
Extremely sharp-witted, Shadow is brooding and always seems to be on the edge, and he usually acts with a cool and businesslike indifference. He is normally quiet and will not speak unless it is necessary to achieving his goals. When push comes to shove, however, Shadow can quickly become extremely aggressive and extensively ruthless. He is also not one to pull his punches for anyone, especially against those who get in his way.
Despite his apathetic nature, Shadow is not completely heartless, although he tries to bury such feelings and thoughts inside of him. For example, when out to kill a seemingly reformed Dr. Eggman, Shadow ultimately choose to give the doctor a chance to prove his benevolence after being reminded of how he himself had turned over a new leaf after trying to destroy Sonic and the world at large, just like Eggman.
Shadow is an anthropomorphic black hedgehog with red stripes on his quills, around the edges of his eyes and on his arms and legs. He has red eyes, a patch of white fur on his chest, and his muzzle is tan. He has six quills on his head, four of which curve upwards, and two that curve downwards, has two spines on his back and a small tail. For attire, Shadow wears white gloves with black cuffs and red tongues, and Hover Shoes which, like his gloves, have black cuffs and red tongues. On each of his wrists and ankles he wears a single gold ring.
Shadow is able to move rapidly with his hover shoes, even if he's slower than Sonic. For a faster shift, he can use the Chaos Control, moving through time and space by disappearing in a green-painted flash of light. Like Sonic, he can perform the Spin Attack and has toe-to-toe combat skills. He can also use the Chaos Spear, which consists shooting bright arrows from the hand.