King Fritz is one of the heroes from After Toontown. He uses an ice staff as his primary weapon. He was turned into a Leader Bot at a point and when King turned into a Crystabot he escaped with King and Jazzy. He usually ends up in places that other toons can't get to or show up at places that other toons are trying to get to before they can.
King Fritz was King's leader and brought him into the agency originally. After that, King trained as hard as he could to surpass him.
King Fritz always was always one step ahead of King in every training exercise that they did.
King Fritz was never surpassed by King when Toontown was still open.
If it weren't for King Fritz bringing King into the agency in the first place, After Toontown would not have taken place, and the cogs would have taken over. (Also if it didn't happen then the writer of After Toontown would have never written the book. He also probably never would have written any books.)
King Fritz introduced King to Cheetah.