Dr. Golden "Prepare-Up!" :
~ "Oh! This is it! I'll make a surprising visit to Security Guard Silent.
She won't suspect anything and finally I'll use my mastered secret ability,
which will bring a lot of FUN and joy... for me, of course! Mwa~ha~ha~ha!"

He's the Big Brain, the Mischievous Mastermind
(the Evil Moustache and Egghead, hiding in the form of a hedgehog) and Scheming all the time against the protagonist to make the things not so easy...

Also... He's the Main Antagonist of Five Nights at Sonic's: Fierce Forces "Imagine It!" *Fan-Comic* and
Titular Antagonist of Fever Daybreaks at Sonic's: Fierce Forces "Aureate Afterglow!!" *Fan-Game* + He's the Leader of Team Golden Sonic.