Captain Metal

Captain Metal, formerly known as Metal Sonic, is the fourth in a line of Metal Sonic robots created by Dr. Eggman. After being destroyed by Shadow the Hedgehog in the Sol Zone, Metal Sonic was rebuilt by an unknown individual and was renamed Captain Metal. Now the leader of a pirate crew, Captain Metal seeks the Sol Emeralds as part of his grand scheme.

Metal Sonic
Shortly after the destruction of both Metal Sonic v3.2 and Metal Scourge by the Suppression Squad, Eggman created a new Metal Sonic model, this time using the newer SXSU-401 engine instead of the typical STH-25, allowing the robot to transport to any other dimension to pursue Sonic. Metal Sonic then left for Moebius against his creator's will to find and attack Sonic and the others in Castle Acorn. Sonic later made an offer for Metal Sonic to help him take out Scourge first, instead of attacking everyone else, and the robot nonchalantly agreed. Scourge didn't give up, however, and rushed to the throne room, followed by Sonic and Shadow. Scourge then turned the tables on everyone by revealing that he had placed Anarchy Beryl in his throne. This managed to transform Scourge into a stronger form; Super Scourge. (StH: #195)

Metal Sonic was temporarily defeated by Super Scourge along with the others and then tried to attack Sonic again when he deduced that defeating Scourge was no longer an option. It was later transported to another location along with Shadow when he tried to override Metal's teleporter engine with Chaos Control. Arriving in an alternate universe, Metal Sonic was employed by that reality's version of Dr. Robotnik to attack everyone, but was once again transported to a different reality by Shadow. (StH: #196, SX: #40)

Metal Sonic and Shadow then ended up in the Sol Zone, floating above an ocean. Shadow tried to convince Metal Sonic to no longer obey Dr. Eggman, but Metal Sonic completely ignored Shadow's request and kicked him into the water before flying off to look for the zone's version of Eggman. Furious that he could not locate that zone's Robotnik, Metal Sonic began attacking Southern Island. Shadow, Blaze and Marine showed up shortly to witness the destruction Metal Sonic had caused. Blaze furiously attacked Metal Sonic, but the machine simply used his powers to reverse Blaze's attack. Neither Shadow or Marine could take down Metal Sonic. However, Shadow tried once again to convince Metal Sonic to work with him, but Metal Sonic simply pointed out they each had different goals, and his was to serve Dr. Eggman. Thus, Blaze set fire to Metal Sonic, and Shadow charged at him. The robot flew towards the Ocean Tornado, and Marine destroyed him with the ship's cannon. (SU: #1)

Captain Metal
At some unknown point, an unknown individual rebuilt Metal Sonic into a pirate themed form using technology native to the Sol Zone and renamed him Captain Metal. (SU: #55)