Barty Crouch Jr is an arrogant and vile son of Barty Crouch Sr., who is secretly a Death Eater behind his father and the Ministry's backs, until he exposed for his crimes and sent to Azkaban.
As the years pass, Crouch Jr plotted revenge, became increasingly insane and served Voldemort in attempt to regain him back to power. Crouch Jr disguised himself as "Mad Eye" as a under-cover, showing hints of his manipulative manner in order to get Harry through the Triwizard Tournament.
Barty Crouch Jr is a slender young man with fair skin, brown hair and eyes. He dons a black leather jacket, shirt, pants and shoes. He also has a Death Eater tattoo on his left arm.
Crouch Jr attended the trial of Igor Karkaroff who was a Death Eater around that time. Igor lists out the names that were involved with the torture and murder of Frank and Alice Longbottom. However, Crouch Jr knows that Igor is going to say his name, and is attempting to leave the courtroom, until Igor says his name to the entire Ministry officials, including Crouch Jr's father Barty Crouch Sr. Crouch Jr attempts to scamper from the courtroom, but Moody repels him and Crouch Jr is restrained by the Ministry officials. His devastated father disowns his son before sending him to Azkaban.