So a few days ago, we found out that two characters had made their comeback, and other things. But there was something that the Sonic Stadium pointed out which I should show you here.
For the concept art of Shadow the Hedgehog, it states that he is a villian in the Boom Series.
Shadow has played evil roles only for a short time (as shown in Shadow the Hedgehog, and in Sonic Adventure 2).
Then again, Sonic Boom is an entirely different universe, which separates it from the original series. So Shadow may be a villian in Boom, while in the original series, he is Neutral.
What do you think of all this? Will Sonic Boom be interesting with Shadow as another villian?