Board Thread:General Discussion/@comment-25819077-20150216184316/@comment-1986314-20150216200828

What reason would Knuckles have to be a villain? He doesn't have any personal vendetta against anyone, nor we would he have a proper motive to turn against any of the current protagonists (unless he were persuaded by Robotnik that something about Sonic was amiss, but that card has been pulled already).

He is just an heir to the guardians of a giant green plot device. If something is not his business or it doesn't involve any sort of emerald hunting, then he wouldn't care.