Witch anime character is not suitable for his role and why
 

i cant think of any, probably because they are made to fit their role perfectly..

You spelled WHICH wrong....

I'm not a big anime fan, so I don't really know any characters that don't "fit their role".

Try giving an example.....? =\

I believe an anime character not fit for their role is Zero from code geass. He just doesnt seem like hes the strong leader type! Maybe a ladies man, but thats it.