E-123 Omega has not made an appearance in a Sonic game for too long. Not counting cameos and spin-offs, he hasn't been seen since the DS version of Sonic Colors! And if you don't have a hand-held, than you haven't seen him since Sonic 06! He has been gone since 2010 in the Sonicverse, and Shadow disappeared too. You see, Kirk Thornton is NOT Shadow, and that isn't just because of his voice. Kirk has a whole different personality. Let me explain; Remember how Shadow was a G.U.N. agent and everything? Fuck that, Kirk doesn't care, or even seem to remember. Pretty much as soon as he came onstage, he wanted the money, and had none of Shadow's honor or dignity. He even replaced the beloved Omega, whom Shadow states (in some paths of The Dark Brotherhood) is his best friend. But Kirk took Metal Sonic over the REAL Team Dark, and he might have known it WAS Metal Sonic, and he was just using a false guise to help Eggman, his creator. (since Kirk is quite obviously an android) He has a different voice, and hasn't even mentioned G.U.N., Omega, Maria, Gerald, his past, or anything/anyone we know the REAL Shadow to be affiliated (and maybe a bit obsessed) with. Also, in Sonic Generations, he says that "I don't know where we are, and I don't care, as long as I get to finish you." (And that was paraphrasing, but the basic point of what he said.) This makes no sense, because Shadow is somewhat an ally of Sonic's, and the REAL Shadow would help him try to save everyone. So the real Shadow is sadly not here, and neither is Omega. "Where are they?" you may ask. My theory is that Shadow has been sent on a long undercover mission for G.U.N., and Omega is with him as extra firepower and a tactical ally. I don't know what this mission is, but it's probably even madami important than all this crap Sonic's been doing in the meantime. Hopefully we'll find out sa pamamagitan ng 2015, and it could be the theme of a new Sonic game with tons of different playable characters and a fascinatingly complex storyline with a final plot so evil that Eggman himself is doing everything in his power to stop it. Sonic Adventure 3 anyone?
