Clu 2 is a program in the Tron series. He was created by Kevin Flynn. He is the villian in Tron: Legacy!!!
As with most programs, Clu 2 appears visually identical - albeit at a younger age - to his creator. He represents an evil twin of Kevin Flynn and a evil embodiment of Flynn's youth. He is addressed as "Your Excellency".
Clu was made by Kevin Flynn for the purpose of creating what Flynn called "the perfect system," taking his user's burden of running the Tron World as his own. Once the self-generated Iso's began to enter the system, he found himself at odds with them, ultimately deeming them a threat to the system's stability that must be destroyed. Clu's strict adherence to his directive also caused him to get really mad with Flynn for spending so much time away from the Grid, leaving him without a guide to follow and unable to take action without Flynn's approval. Eventually he conspired to take control of the Grid, reasoning that he was made in Flynn's likeness and thus, for all intents and purposes, he was the Creator.
Defined by his duty, Clu was a perfectionist who sought to halt any evolution in the system. Since the Isos were not created by Flynn, he blamed them for the various glitches in the system, even going so far as to suggest that the Isos themselves were responsible for things like these bugs called grid bugs that derezzed (killed) people.