Well, a character that is the most evil in fiction often has a goal that is inherently wrong and harmful. Like the White Witch in 'The Chronicles of Narnia'. She wants to keep Narnia in an eternal winter and kill all the Narnians who oppose her. Her actions are cold - blooded and her heart is filled with hatred. They also don't show any mercy or remorse for their actions. No matter how much pain and suffering they cause, they just keep on with their evil plans without a second thought.
One factor is their motivation. If their motivation is purely self - centered and involves harming others on a large scale, they can be seen as very evil. Take Darth Vader from 'Star Wars' for instance. He was initially lured to the dark side by the promise of power, and in the process, he committed many atrocities, like destroying entire planets. However, his character also has some complexity as he later redeemed himself, but during his time as a Sith Lord, he was a symbol of great evil. Another aspect is their methods. Characters who use cruel and sadistic methods to achieve their goals are often regarded as evil. The White Witch from 'The Chronicles of Narnia' froze Narnia in eternal winter and turned many of its inhabitants to stone, showing her extreme cruelty.
The scope of a character's influence also matters. If a character has the power to control the fate of entire universes, like Eru Ilúvatar in 'The Silmarillion', they are clearly very powerful. Their decisions can create or destroy entire worlds, and all other beings are subject to their will in some way. This kind of overarching power is a key factor in determining the most powerful person in fiction.
One of the most evil fictional characters is Lord Voldemort from the Harry Potter series. He is responsible for countless murders, including the deaths of Harry's parents. He wants to purify the wizarding world by eliminating those he deems unworthy, mainly Muggle - born wizards. His actions are driven by his thirst for power and his belief in wizarding supremacy, which makes him extremely evil.
If a villain enjoys inflicting pain and suffering on others without any remorse, they can be seen as extremely evil. Hannibal Lecter from 'The Silence of the Lambs' not only kills people but also eats them. He takes pleasure in the horror he causes, which is what makes him so terrifyingly evil.
Voldemort from the Harry Potter series could be considered one of the most evil. His pursuit of immortality and willingness to kill countless innocent people make him truly evil.
Power combined with a lack of morality. For example, if a powerful alien race in science fiction uses its advanced technology to enslave weaker races just for fun or to gain more resources without any ethical consideration. That's pure evil. They could be doing it on a large scale, across galaxies perhaps, and not care about the suffering they cause.
Their impact on the story and other characters is another factor. In 'A Song of Ice and Fire', Joffrey Baratheon is detested for his sadistic and cruel nature. His actions towards Sansa Stark and others are so heinous that his character is unforgettable. His evil drives much of the political and personal drama in the story.
The complexity of their evilness. Hannibal Lecter in 'The Silence of the Lambs' is not just a simple killer. He's highly intelligent, cultured, and yet has this dark side where he can be extremely cruel. His ability to manipulate those around him while being locked up in prison adds to his memorable nature.
One of the most evil characters in fiction is Lord Voldemort from the Harry Potter series. He is responsible for countless murders, including the death of Harry's parents. His goal was to take over the wizarding world and rule with an iron fist, eliminating all those who opposed him, especially Muggle - born wizards.
Innovation is another aspect. Tony Stark from the Marvel universe is a great example. He invents amazing technology like the Iron Man suit. His ability to think outside the box and create solutions that no one else has thought of, whether it's for combat or for other scientific purposes, makes him a strong contender for being one of the smartest in fiction. He also has the business acumen to run his company and use its resources for his inventions.