Metal Sonic

While usually serving as Eggman's obedient and silent enforcer, Metal Sonic is an intelligent robot with a very dark side. Cold-hearted and ruthless, he is obsessed with proving his superiority to Sonic and eliminating him for good to the point where he has rebelled against Eggman more than once to achieve his goal. However, he always fails in the end, only to later return more powerful than before. To this day, Metal Sonic remains one of Sonic's most dangerous foes.