Design wise. Not personality. I know at least two concepts for an evil Optimus Prime. The first is the Black Optimus. A.K.A. Nemesis Prime A.K.A. Black Convoy A.K.A. Scourge, and the second is Shattered Glass Optimus. As the description implies, it's a black redeco of Optimus. I don't think it's special because I see it as just a Black = Evil concept and not creative. The second one is Shattered Glass Optimus Prime. I dig this design more than the first one. It gave a unique look for an evil Optimus from the purple paint job, to the body scratches, the "offensive" tattoos as I like to call them, and to the shattered windshields!