For those who may be new to Deviantart or those that may be new to viewing the Masterful1 profile:
Sonow is an original creation by TOG and I, Bigjob, originally meant for Super Mario Bros. Z; however after the show was cancelled we saw Sonow as just another spritesheet that would be interesting to make and expand upon. Sonow is in no way akin to the original creation Shadic, Sonow has a different name, of course, but more importantly a different persona: He is a generally darker tone with a darker personality, and he likes to play it dirty when it comes to fighting, as you can see from the "Sparta Kick" in the spritesheet.
All in all, Sonow is a fan fusion character for all to enjoy, and, of course, if you want to use him in any project just give credit.