Some evil parents are simply self - centered. They don't really consider their children as individuals with their own needs and feelings. In 'Matilda', her parents were so self - centered that they didn't notice how unhappy Matilda was. They were only focused on their own mundane and selfish pursuits, like watching TV and making money in a not - so - ethical way, without any regard for Matilda's well - being or her amazing intellectual capabilities.
Another motive could be survival. If their home planet is dying, they might be looking for a new place to live. This is seen in some stories where the aliens are refugees seeking a new home, but their arrival often causes conflict with humans.
Ransom is a very common motive. In many stories, the kidnappers want a large sum of money in exchange for the safe return of the victim. Another common one is revenge. Maybe the kidnapper has a grudge against the victim or their family. And sometimes it's for power or control. They might want to use the kidnapped person as a pawn to get something from a larger entity, like a government or a big corporation.
One common motive is conquest. They want to take over planets, including Earth, for resources or to expand their territory.
In fantasy fiction, parents can be protectors. For example, in 'The Lion, the Witch and the Wardrobe', Mr. and Mrs. Pevensie send their children to the countryside for safety. They can also be sources of mystery. Sometimes a character's parents have a hidden past or special powers that are gradually revealed as the story unfolds. And they might be the ones who pass on important knowledge or skills, like in some stories where a parent teaches their child magic or survival skills.
Power hunger could be a motive. Tony already has a lot of power with his technology, but if he becomes obsessed with having more and more, it could lead him to evil. He might start to see others as obstacles to his power gain.
A sense of pride and arrogance is also common among them. They believe that they are superior because of their magical abilities and look down on those who are less powerful. This often leads to their downfall in the end, as their overconfidence makes them underestimate their opponents. For instance, many evil wizards are defeated by heroes who are not as magically strong but have other qualities like courage and unity on their side.
One common type is the evil of greed. Characters may kill or steal because they want more money or possessions. Another is revenge - driven evil. Someone might seek vengeance for a past wrong, leading to a string of crimes. Then there's the evil of jealousy, where a character is envious of another's success or relationship and resorts to criminal acts.
Power and control can be motives too. In some cases, a person wants to have power over another. They think that by blackmailing, they can make the other person do what they want. For instance, in a workplace, an employee might try to blackmail a boss to get a promotion.
Perhaps the writer wants to explore the nature - vs - nurture concept. Harry grew up in a difficult environment, and in fanfiction, this could be twisted to make him turn to evil. Another reason might be to introduce a more complex villain. Instead of a typical bad guy, having Harry as a secretly evil character adds a new layer of depth to the story.
It could be a revenge plot gone too far. Suppose her parents did something in the past that she just found out about, and in her new dark persona, she decides to take the ultimate revenge. Or perhaps she has fallen so deep into the dark side that she no longer values family and sees them as just another obstacle in her path of darkness.