User blog comment:Smash The Echidna/A guide to Fan Characters and Roleplaying/@comment-7637833-20140916221841/@comment-1942179-20140916223755

Uuhhmm...I guess, maybe? Unlike Knuckles, whose whole family is presumed to be dead along with the rest of his tribe, we really don't know anything about Sonic's family, canonically speaking. So I guess it isn't too farfetched to have a distant cousin, as they wouldn't be as closely related as say, direct siblings.