Mecha Shadow was a recurring character in the series. He was a recurring antagonist in Season 2, being a main antagonist of the Master Emerald Retrieval Arc and the Robot Rebellion Arc. He was one of the robot counterparts of Shadow and was the most dangerous one. He was destroyed by Shadow in the Robot Rebellion Arc.
2 months after the Space Colony ARK was destroyed, Dr. Eggman found his blueprints of Mecha Sonic and used them to design a new robot based on Shadow in order to eliminate Shadow. However, Dr. Eggman feared that Mecha Shadow would betray him like Mecha Sonic had, so he shut Mecha Shadow down and kept him in a storage facility. On June 5, 2010, Mecha Sonic broke into the storage facility that Mecha Shadow was in and freed him. He proposed a partnership between him and Mecha Shadow so they can kill Dr. Eggman together. Wanting revenge, Mecha Shadow agreed to this partnership.
Mecha Shadow is as cruel and heartless as Mecha Sonic, as seen when he was attempting to kill Tikal and Chaos despite them having done nothing to him. He strongly dislikes Dr. Eggman due to him keeping Mecha Shadow deactivated. He also dislikes Shadow due to losing to him.
- Super Speed: Mecha Shadow can fly up to speeds faster than Mach 1 (768 mph).
- Super Strength: Although it is unknown how strong he is, Mecha Shadow is strong enough to tear metal apart.
- Flight: Mecha Shadow is able to fly due to having built-in jets.
- Teleportation: Mecha Shadow is able to teleport by converting his body into data.
- High Physical Durability: Because he is made out of metal, Mecha Shadow can survive most physical attacks and recover from said attacks quickly.
- Martial Arts Specialist: Mecha Shadow uses a fighting style revolved around his robotic capabilities, along with his speed and strength.
- Energy Manipulation: Mecha Shadow can use energy stored within his body to create energy beams and a shield.
- Fire: Mecha Shadow can be damaged by fire-based attacks.
- Super: By absorbing energy from the Master Emerald, the color of Mecha Shadow's body turns pale gold. In this form, Mecha Shadow's strength, speed, and durability are greatly increased, similarly to Shadow's own Super form.
- Metallix: By absorbing a larger amount energy from the Master Emerald, Mecha Shadow's body changes completely, becoming more slim and slightly smaller. In this form, Mecha Shadow retains the same benefits as the Super form, only 3 times more powerful. He also gains the ability to create and wield energy swords.
- Mecha Shadow vs. Shadow (lost)
- Mecha Shadow and Mecha Sonic vs. Mario, Sonic, Yoshi, and Silver (won)
- Mecha Shadow vs. Mario, Luigi, and Shadow (lost)