Sonic is one of the lead characters. He makes his first major appearance in episode 3, but I'm casting him now because he's a main character and he's someone I definitely cannot voice. 

Sonic has had many different voices over the years, so you can go for any impression. I love all Sonic voices equally (yes, even the voice from the Sonic movie). He needs a lot of energy in his voice, so be prepared to deliver his lines in his loud and cocky style.