These are not my characters. They belong to a former member of DeviantArt named Shain-Groothom.
He once posted a forum thread asking us to draw improved versions of his characters. They're originally featured in his Imgur account, and I'm sorry to say he drew them rather crappily. If you don't believe me, take a look for yourself:

From left to right:
Blue the Hedgehog: http://i.imgur.com/wlTpQjY.jpg
MrBlackDarkness the Hedgehog: http://i.imgur.com/2NWpsae.jpg
Mail Man: http://i.imgur.com/K9mQ37B.jpg
Polarus Ursard: http://i.imgur.com/bkatvnr.jpg

Blue and MrBlackDarkness based on Sonic the Hedgehog by SEGA
Mail Man based on Mega Man by Capcom