Baron Von Rotten, better known as Judge Doom, is the much-feared Judge of Toontown. Despite presiding over a city of Toons, Doom is totally without mirth and passes capital punishment on Toons who break the law, placing them in a chemical vat of turpentine, acetone and benzene (essentially oil, paint thinner, and film dissolver) which he dubs "The Dip". This concoction will dissolve Toons, permanently killing them. He wears gloves supposedly to avoid the mess (but as it is soon revealed, it is actually to prevent himself from being dissolved). The Judge employs Toon henchmen (the "Toon Patrol") to assist him in hunting down Roger for the murder of Marvin .
Judge Doom displayed two very different personalities in the film, both equally menacing to his enemies.
Judge is a calm and reserved man without mercy and brutally executes those who perceives as guilty or stand in his way. He has an ambition to erase Toon Town in order to create a freeway due to its profit and potential benefits; buying then dismantling the "red car" to avoid competition and taking money from his theft at the bank to launch the project. Judge Doom also possess cunning as he lures out Roger Rabbit with the "Shave and a Haircut" trick. He had a Hitler complex which he tries to deny to the extent of disguising himself as a human to try to rid the world of Toons, despite being one himself. However when he was being run over, he acts like a Toon (screaming incomprehensible noises in fear) and does not deny it once the jig was up, but "not just any Toon"...
Toon, After Judge Doom re-inflates himself and reveals himself as Teddy's killer with reunion with Eddie he tells him why he should not remember his eyes, but his voice (which grows higher until it reaches a horrifyingly high pitch) and his eyes turn to daggers ready to kill him. Though he doesn't talk again until his demise, he pursues Eddie when he was running away, turns on the cannon to melt Roger and Jessica once he was pushed to the ground, punching Eddie with an anvil, turning it into an buzz saw to demonstrate how lethal it was and the swirling eyes with a wide grin as he was gradually getting closer to kill Eddie. All these traits show he was a deranged and sadistic psychopath who enjoys making his victims watch as their friends die and loves to kill them slowly in the most agonizing way. He does have fear of death, as he instantly panicked as soon as the Dip hit him and screamed as he dissolved.
In Ultima, Doom was resurrected by Hades in order to be recruited for his cunning intelligence and sadistic behavior. Doom joined so that he could seek his revenge on Eddie Valiant and Roger Rabbit for destroying him before. He ahs private control over the Heartless of Toontown and Wonderland. Doom emerged on the scene when he kidnapped Kristy in ransom for the UltimaCrystal, until he was defeated by Kristy whom empowered by the crystal itself.