Villains exist to perform evil acts, aiming to profit, conquer, or create chaos that the heroes must stop or prevent. Great villains are able to pose a real threat to the heroes and are extremely challenging to defeat.
Not every villain is flawless, as they are usually defeated and slip up from time to time. Some villains have done their job so poorly that their decisions have helped the heroes in some way. It is thanks to a villain's extreme lack of foresight or their overconfidence that they do things that lead to their own downfall, with minimal contribution from the heroes themselves. Moments like these can either be hilarious, or completely frustrating to fans.
10 Bleach: Sosuke Aizen Nurtured His Enemy's Growth
Aizen always boasted about his ability to be ten steps ahead of everyone else. Most of his moves were carefully calculated, making him one of Soul Society's most dangerous enemies. Aizen saw Ichigo Kurosaki's birth as a happy, unforeseen event.
He chose to nurture Ichigo's growth by sending Hollows his way and even stationing Rukia Kuchiki in his town so she would share her powers with him. He saw Ichigo as an experiment he could learn from, but his fight against Ichigo severely weakened him.
9 The Promised Neverland: Krone Took A Huge Risk That Didn't Pay Off
Sister Krone was the secondary caretaker that Isabella brought in to keep an eye on the children. From the start, Krone's intention was to take Isabella's position from her. After discovering that the children wanted to escape, she decided to conspire with the children, answering each of their questions.
Isabella was aware of Krone's intentions, leading to Krone's demise at the hands of a demon. The clues and answers that Krone gave the children saved their lives.
8 Pokémon: Team Rocket Lost To Ash Despite Having Giovanni's Pokémon
For some reason, Giovanni temporarily left the Team Rocket trio in charge of Viridian Gym. Given the fact that they are constantly losing to Ash, the three were doomed from the start.
Despite their attempts to cheat and the fact that they were armed with some of Giovanni's powerful Pokémon, they still managed to lose to Ash. They refused to hand over the badge at first but ended up dropping it as they were blasted away. If Ash had fought Giovanni while the villain had Mewtwo, Ash would have lost instantly.
7 Dragon Ball: Emperor Pilaf's Wish Was Foiled By Oolong
Emperor Pilaf and his cronies managed to gather all of the Dragon Balls, eager to fulfill his wish of ruling the world. His dreams never reached fruition. Although he had the heroes in captivity, he took far too long to make his wish, and he spent most of his time admiring his hard work.
This gave Oolong enough time to fly out of the small hole Goku had blasted through their prison, and he jumped in to wish for women's underwear before Pilaf could make his wish.
6 Sword Art Online: Akihiro Kayaba Was A Victim Of The World He Created
Akihiro was responsible for trapping thousands of players in Sword Art Online, where death was just as real and permanent as it was in the real world. Since Kirito had discovered his identity, he gave him a chance to defeat him in a solo battle, after turning off his immortality.
Kirito had no choice but to kill him in order to free the players that were still trapped in the game. What makes Akihiro's actions seem especially foolish is the fact that he couldn't remember his own motivations for killing so many people in the first place. At the very least, he kept his promise to free the players after his defeat.
5 Sailor Moon: Queen Beryl Didn't Send More Minions To Destroy The Sailor Scouts
Beryl sent her minions to collect human energy to revive Queen Metalia. Although more Sailor Scouts kept appearing to foil their plans, Beryl did not send nearly enough people to defeat them.
Additionally, she would have found much more success in collecting energy from more than a single place at a time. Her worst mistake was punishing Jadeite before he could reveal the Sailor Scouts' secret identities.
4 Demon Slayer: Gyokko Was Too Focused In Breaking Hotaru's Concentration
After Gyokko trapped Muichiro Tokito in his Blood Demon Art's Water Prison, he left the Hashira without ascertaining his fate. Instead, he came across Hotaru, and was hyper-focused on breaking his concentration. He was wildly jealous of Hotaru's fixation on the sword he was tending to, as he never experienced that kind of concentration as an artist.
As he was occupied with someone who wasn't a threat to him, Muichiro had more than enough time to safely break free.
3 Howl's Moving Castle: The Witch Helped Sophie More Than Once
Despite her wicked intentions, the Witch of the Waste actually did more good things for Sophie than harm. Turning Sophie into an old lady out of pure jealousy motivated Sophie to finally leave her home and live her life. Ironically, she met Howl, the very person the Witch wanted to keep her away from.
Towards the end of the film, the witch seized Calcifer out of her greedy desire to own Howl's heart. This led to Sophie's realization that she could break Howl's curse, and keep the heroes away from the war zone.
2 Demon Slayer: Muzan Kibutsuji Killed The Doctor That Saved His Life
Muzan was so ill that he wasn't expected to live past the age of 20. A doctor used experimental medicine to cure his disease, but assuming that it wasn't working, Muzan killed him out of rage.
The medicine was effective, and because the doctor did not have time to utilize his Blue Spider Lily medicine, Muzan wasn't able to go out in the sun. Thanks to Muzan's impatience, people were safe from him and his minions during the day.
1 Fairy Tail: Zeref Managed To Save His Brother's Life At A Terrible Cost
Zeref learned magic and applied his knowledge to search for ways to revive the dead, particularly his brother Natsu Dragneel. His research met criticism, and his mentors warned him that the god Ankhseram would punish him. This came to pass, leading to his immortality and expulsion from his academy.
He shifted his efforts into finding something that could kill him and succeeded in reviving his brother as the ultimate weapon.