Doctor Finitevus

Doctor Finitevus was a prominent villain in the Archie comics incarnation of Sonic the Hedgehog and was a rogue echidna who caused untold carnage in his personal quest for power (unlike in the games in Archie comics Knuckles was not the last of his kind, a plot-twist later revealed in Sonic Chronicles).

Doctor Finitevus is notable as being one of the darker Sonic villains even by Archie standards and his list of crimes are extensive - dating back many years and several issues and storyarcs.