Pokémon Ranger: Guardian Signs: Purple Eyes. Before we even learn he exists, he's beaten Rand within an inch of his life and kidnapped both his wife and daughter. Later, he beats the daughter up, too. He eventually mugs the elderly Societea members, hijacks the villain's plans, makes himself immortal, pumps up Mewtwo's power higher than it should ever be, and then commands Mewtwo to finish off Dr. Edward. And when Rand takes the shot for Edward, Purple Eyes is simply amused and continues to attack anyway, even taunting Rand's daughter about it. After you beat him, he points out that the Sky Fortress is now plummeting and will wipe out all of Oblivia, before laughing. Rand's wife said that the ruins she and her daughter were captured and tortured in is the only place that gives her recurring nightmares. In the last Extra Mission, in which an enraged Arceus is passing judgment on the human race, he arrives in person. His imprisonment and constant questioning has not redeemed him, but instead turned him into a Misanthrope Supreme who no longer wishes to rule over all humans, but instead Kill All Humans. He begins preaching to Arceus that it should go through with the destruction, but to allow himself to act as its Dragon due to their similar beliefs about humans, which only enrages Arceus more.
Diamond and Pearl: Pokemon Hunter J as her name implies, she hunts rare Pokemon to sell on the black market, and has no qualms with stealing them from other trainers. She is willing to go to any length in order to capture these Pokemon for her clients, including attempted murder on her fellow humans. In her first appearance, she drops a section of her airship containing several of her own men, and the Pokemon that she’d stolen, just in order to be rid of our 10-year-old protagonist, who was in the same section of the ship. She shows absolutely no hesitation or remorse for this action, and Ash had only been a slight inconvenience to her at that point. In her follow-up appearances, she continued to demonstrate her sociopathic, greedy, ruthless nature, as well as her total disregard for any form of life by continuing to steal rare Pokemon, setting fire to a large section of densely populated forest in order to kill Ash, ordering her Salamance to attack humans directly, commanding her Drapion to squeeze the life out of Ash, and abandoning one of her clients to the police the second after she got paid. In the 800+ episodes of the Pokemon anime, she’s the only character who has proven to be purely evil with no redeeming qualities.
Pokémon: Zoroark: Master of Illusions: The Big Bad, Grings Kodai, is a powerful businessman who discovered one of Celebi's Time Ripples. Gaining its power at the price of annihilating the nearby city's plant life, Kodai used this power for his own greed. In the current, Kodai kidnapped a Zoroark's baby Zorua, importing the baby into another region and using blackmail to force Zoroark to terrorize innocents to make himself look good. He intended to renew his abilities by touching the Time Ripple again, at the threat of once again devastating the ecosystem solely for the money. Once Zoroark tracks Kodai down, Kodai threatens Zorua's life, electrocuting it with his gauntlet to almost fatal extents to prove he was serious. Upon being tricked by Zoroark, Kodai loses it and instead electrocutes Zoroark to death in his fury, just as the two were finally being reunited. An ambitious and selfish opportunist of the worst kind, who only cared about himself, Grings Kodai managed to be one of the most despicable humans in the Pokémon franchise.
Pokémon: Diamond and Pearl Adventure: Charon was a money-obsessed Jerkass in the Pokémon games, but here his method of introducing himself is to order his agents to suicide bomb a crowded stadium. He holds no regard for the lives of others and plans to control the world with money made from selling legendary Pokémon. Charon captures the organization's previous leader, Cyrus, and tries to kill two of his top officers when they leave to find him. Cyrus goes on to rally the remaining agents against Charon, despite previously trying to destroy the universe.