Cyrille Le Paradox was the main villain of Sly Cooper: Thieves in Time. He used a museum to cover up his crimes of trafficking priceless stolen items, and collecting in France. Le Paradox intended to use time travel to create a fake royal ancestry so that he would become highly valuable when he returned to the present. Le Paradox also desired to ruin the Cooper Clan and potentially erase their history. One way he planned on doing this, was by stealing all of the Cooper Ancestor's canes (He ultimately failed in doing so).
Like Sly, Le Paradox comes from a clan of master thieves. His clan was called the Le Paradox Clan. Back in the day, Sly's dad, Conner Cooper, stole the world's biggest diamond, propelling him to a legend. However, Le Paradox's father had planned to steal the diamond first, and even frame Conner for it. Conner, however, was too quick and got to the diamond first. Instead, Le Paradox's father was caught and imprisoned for life.
Le Paradox had spent time in prison himself. It was in prison where he learned and developed the skills of convincing others to do his dirty work, as well as the art of bribery. After his release, he used these skills to form his own clan. After accomplishing a number of heists, Le Paradox vowed to erase the Coopers from history and avenge his father.
During the final battle of Sly 4, Sly takes on Le Paradox on his blimp, which is falling apart as they duel. Eventually, Le Paradox slips and falls, barely hanging on tot the blimp. He tricks Sly into helping him up, then steals Sly's paraglider and falls. However, as he floats down, he is hit by a passing airplane. Le Paradox then fell into the waters of Paris, miraculously surviving by using a piece of the fallen airship to keep him from drowning. He was then brought to shore and arrested.