Discord is the madgod of chaos and disorder, and a significantly better villain than piece of crap Nightmare Moon was. Seriously she was a dothack villain.
Discord is voiced by John de Lancie of Q fame and is generally a suave evil bastard. Like Q, he is fond of inventing "games" with complex rules, then tricking his unfortunate guests into breaking these rules so that he can laugh at them.
Discord is extremely arrogant and often ignores unexpected retaliations against his convoluted plans.