Some of us may of wondered, why did Devan end up so evil? We know why he despises rabbits, but there are many nicer ways to express dislike than attempting to enslave a planet. He has also been described as "hideously dorky", could insults as a kid led to his eventual mental state?
I don't believe so.

Ladies and gentlemen, I have stumbled upon an earth-shattering piece of information, so secret it is banned in America and Europe.

My fellow Jazz Fans, Devan is evil because as a child he was... a nazi.

Need proof? There is photographic evidence right here:

Need even more proof? In the cartoon, the young turtle is referred to by his commander as "SCHIEL!" or however you spell a stereotypical german accent saying "Shell". Which as we all know is Devan's last name.

The brothers Warner may have tried to hide the secret of Devan's past, but thanks to YouTube and punks who decide stuff shouldn't be banned (or that it's just funny because Bugs and Daffy fighting nazis!!) the truth has been revealed.