Complete Monster/Naruto

A few of these show up in Naruto:
 * Orochimaru: With virtually every appearance in the series, another irredeemable crime is added to Orochimaru's long list. From his first introduction where he is literally wearing somebody else's face to forcing three of the Hokages into a Fate Worse Than Death, he just becomes more and more of a monster. Things are only upped in Shippuden as his body's abilities become increasingly monstrous and it is revealed that he had previously performed genetic experiments on infants, and out of them, almost nobody but Anko and Yamato survived.
 * Gato, the repulsive Big Bad of the Land of Waves arc, was at least bordering on this trope. A Corrupt Corporate Executive who's also a drug dealer/smuggler, he was primarily characterized by being extremely selfish, greedy, cruel, and vile to the core. When you publicly crucify someone for false and petty reasons, there's pretty much no going back for you. And kicking a dead boy in the face doesn't win you any points either, ya rotten dirtbag.
 * Anime only villain he may be, but Shiranami of the Tsuchigumo clan is one nasty piece of work. He killed his own father in an attempt to obtain the Dangerous Forbidden Technique which his father had been protecting just for the money it could get him, nonchalantly enslaved an entire village, pretended to sympathize with Hotaru's (the container of the forbidden jutsu) loneliness, and offered to help her restore their clan before revealing that he doesn't care about Hotaru or the clan at all, forcibly activated the forbidden jutsu inside the poor girl (which she had been trying to get rid of, but he manipulated her into keeping it) and considered her a mere "tool" that he wants to use to "steal the world" for himself. He cheerfully describes the act of killing his father to Hotaru and tells Naruto and Utakata that the main reason he killed him is simply because he's greedy. Nonetheless, Shiranami thinks that, compared to Utakata, who doesn't care about his own village either but still cares about Hotaru, he's a "pretty fine" person. He admits that they don't need to worry about Hotaru because she will live on with him in the world he hopes to create, but she will spend the rest of her life as his "tool/weapon" with no free will of her own. Oh, and episode 150 ends with him forcing the forbidden jutsu activated!Hotaru to fight Naruto and Utakata against her will. He has his men go after/attempt to murder people who try to prevent him from accomplishing his insane goal, which includes Utakata, Naruto, Sai, Yamato, Tonbee, and Sakura.
 * Hidan. Unlike most villains, he has no Freudian Excuse (unless you consider boredom one) and treats murder like a fetish. Also, he had a sickening satisfaction from killing Asuma and later insulted him in front of his student. It is satisfying to know,, that his immortal jutsu is supplied by his ritual, meaning he'll rot before he dies of malnutrition. Also,.
 * And last there's the series' ultimate Big Bad,, who plans to destroy the entire world so that he can control all that remains. He uses the excuse that he wants to make a world where there is no more struggling and everyone is equal, but delving into his backstory and motives makes it pretty clear that he truly just wants to be God amongst all other men because he's a sore loser. He cursed his entire clan as well. His co-Big Bad, , is arguably even more heinous, making him a contender for this trope too.
 * 13 years before the series started, he unleashed the Nine-Tails against Konoha and fought Minato Namikaze, the Fourth Hokage, who was forced to seal the Nine-Tails inside his own son, Naruto, to stop him in a Thanatos Gambit -- with the unfortunate side effect of orphaning this kid as well as subjecting him to being treated like hell for a reason he wouldn't even come to understand until after starting out at ninja school. Predictably, he never even bats an eyelash at this kid whose life he has completely ruined until years later when he decides it's time to implement his plans and Naruto is one of his main targets due to being a jinchūriki as well as the one guy who can become strong enough to stop him. He is not above threatening a newborn infant and attempting to kill Kushina right after she gave birth. His evil plan is basically an Assimilation Plot in order to enslave the entire world and make reality how he sees fit.