Fool is the main antagonist of Tail Concerto.
Fool is a black marketer who specializes in illegal artifacts. He acts snobbish and loves plotting and scheming. His overall personality is that of a typical cartoon villain while not being afraid to commit violence against those who attempt to thwart his plans, which is usually done through explosives.
Fool is a purple Felineko with the same colored hair and golden eyes. He dresses quite proper for being a criminal, dressed in a fancy black suit, top hat, and dress shoes (all articles of clothing are purple in-game). He walks with a cane, though whether or not he simply has it for style is unknown.
In Tail Concerto
Fool made a deal with the Pris sisters that if they collect all five crystals scattered about the land of the Prairie Kingdom, he would help make a country only for Cat-People.
Later it's revealed that the crystals are the key to resurrecting the Iron Giant and that Fool's true intention was to use the giant to take over the land, but his plan completely failed in the end, as the Iron Giant did not follow his orders and ended up swallowing him along with the Egg Stone. After the Iron Giant's deactivation, Fool is shown to have survived and is seen floating in the "sea" below Prairie.