In some cases, characters start off as genuinely good people, but circumstances tempt or force them into a life of villainy. In other cases, characters are actually evil all along, but their sinister motivations are not revealed to the viewer until the other characters learn the truth. In one case, a character tries desperately to make himself good, but ultimately gives in to his innate villainy. No matter the circumstances, it's fascinating to watch someone who seemed to be morally just give in and embrace the dark side.
At the start of Death Note, Light Yagami is an ordinary teenage boy with a strong sense of justice. When he picks up a magical notebook that lets him kill anyone whose name he writes down, he's initially reluctant to use it. However, he quickly decides to put his newfound power to use, and starts taking out criminals. His motives are pure, if dangerously misguided, and he genuinely believes that he's making the world a better place.
Soon, Light begins to do things that are inarguably unjust. He starts killing people who have done nothing wrong, just because they stand in his way. He even considers letting his own sister die to avoid getting caught. The Light Yagami from the beginning of the series would be disgusted by the person he becomes.3,895991Is this a drastic change of heart?
Griffith of Berserk is so beautiful (and so evil) that he's literally supernatural. While he starts off as an honorable — if somewhat arrogant — person, he changes quite a bit over the course of his life.
At first, Guts and Griffith are partners. It's not entirely equal, since Guts was forced to become a mercenary by Griffith after losing a duel, but Griffith considers it a partnership nonetheless. When Guts eventually wins a duel that earns him his freedom, Griffith is furious, and starts pursuing his true goal, which is to build and rule over his own kingdom. In order to accomplish this, he joins up with a powerful group called the God Hand, and uses an eclipse to kill every one of his followers in order to fuel his own transformation into the powerful Femto.
Despite all this, Griffith does truly want a normal life, so watching Guts and Casca love each other fills him with jealous rage. What he actually wants is to marry Casca and have children with her.2,290585Is this a drastic change of heart?
Ken Kaneki of Tokyo Ghoul starts off as a mild mannered young literature student who's drawn into something grotesque. He's attacked by a ghoul (an anthropomorphic being that eats human flesh), then turns into one after he accidentally receives ghoul organs in a transplant. His giving into his newfound desire to eat human flesh doesn't make him villainous; he finds a way to do so ethically after he meets the members of Anteiku. It's only after he's brutally tortured that he loses his desire to be kind. When this happens, he becomes willing to act ruthlessly towards others if it means furthering his own goals.3,505963Is this a drastic change of heart?
The protagonist of Yu-Gi-Oh! GX, Yuki Judai (known as Jaden Yuki in the dub) starts the series as a happy-go-lucky guy with good intentions. In Season 3, all that goes out the window. Like everything else that happens in Yu-Gi-Oh!, his descent starts with a kidnapping. After his friend Johan is forcibly taken to a world that resembles Hell, Judai follows him with the intention of rescuing him, and the rest of his friends follow suit.
This is exactly what Yubel — his ex-girlfriend from a past life — wants. She takes over his body and brain, turning him into an evil overlord called the Supreme King. As the Supreme King, Judai enslaves and kills thousands of duel spirits, and also temporarily murders most of his friends. While he eventually does comes to his senses, he ends the series callous and indifferent to the feelings of others.976332Is this a drastic change of heart?