* In ''Manga/RurouniKenshin'', there are several:
** Jin-E Udo is a remorseless BloodKnight and SerialKiller who lives for murder. In the era of peace, Jin-E makes his living as a PsychoForHire assassin who goes out of his way to slaughter as many human beings as possible for the fun involved. when he encounters Kenshin Himura again, Jin-E becomes obsessed with turning Kenshin into a killer like him and kidnaps his LoveInterest Kaoru Kamiya. When Kenshin arrives, Jin-E uses his powers of hypnosis to freeze her in place and force Kenshin to break his vow to never take another life as the hypnosis will be lifted only if Jin-E dies and Kaoru's body will shut down within minutes.
** Kanryu Takeda is a SleazyPolitician and SmugSnake who earns a massive amount of profit by peddling opium to hook innocent and desperate people on. To this end, he enslaves Doctor Megumi Takani, having killed her mentor, and forces her to create a drug to destroy lives. Kanryu, when his elite bodyguards, the Oniwaban Group are defeated, Kanryu unveils a Gatling gun and opens fire on their leader, killing the rest of the group when they try to save him. Kanryu simply gloats how invincible he is before trying to kill everyone else, bragging about how his money gives him the right to do anything he wants.
** Gein, Enishi's [[TheDragon Dragon]]. He's a PsychoForHire, BloodKnight, and an all around sicko who joins Enishi's campaign and offers him advice on MindRape-ing Kenshin, not for revenge, but for kicks and a chance to test his abilities. He makes puppets out of corpses, kills or murders pretty much everyone who crosses his path, works as an arms dealer, sees war as a chance for fun and intellectual masturbation, and was the mastermind behind the plan to fake Kaoru's murder, just to screw with Kenshin's head. On top of that, he was [[MeaningfulName named after]] [[SerialKiller Ed Gein]].