In ' Little Mouse on the Prairie', he inadvertently rescues the Mousekewitz family from being eaten by Waul, having his gang beat Waul up for cheating him in a gambling game earlier in the episode.

In another episode he reveals a soft side, taking a liking to Yasha Mousekewitz and finding her too adorable to eat when she wanders into his hideout in ' Babysitting Blues'. In this episode he orders a 'Mouse Slapper' which fires nets on mice, and he terrorizes the town with it, but is easily subdued by hired lawmouse Clint Mousewood.

In one episode, ' Mail Order Mayhem', he plays out as the main bad guy, working with two other cats Slim and Felonius without Cat R. However, after the scheme fails, William beats Waul senseless. Waul after being promised that his scheme will result in them getting to eat mice. The very first episode, 'Fievel, the Lonesome Ranger', has Sweet William forge an alliance with Cat R. He can be considered even more dangerous than Waul because of his aggressive nature.

It appears that after Waul was ousted from Green River at the end of Fievel Goes West, Sweet William no longer took orders from Waul unless there was something in it for him, and in fact beats Waul up in many episodes. But in Fievel's American Tails he is elevated to a main villain with a gang of his own. In An American Tail: Fievel Goes West, William appears only as a background character, like most of the other members of the gang. He was the minor antagonist in An American Tail: Fievel Goes Westbefore playing a bigger role as the secondary antagonist in Fievel's American Tails. Sweet William is a large, muscular member of Cat R.

Nott the brave character sheet