Due to the large number of anime, there are so many immature and flat-out annoying characters to discuss. These characters are hated the most by their respective fandoms.
This list will rank these characters from the most mature (10) to the least mature (1).
Note: This article is subjective and reflects the author's opinion.
Ten anime characters who have displayed the most childish behavior
10) Boruto Uzumaki (Boruto: Naruto Next Generations)
The titular protagonist, Boruto Uzumaki, has grown a lot since the beginning of his series. He is now incredibly mature and forging his path in the Shinobi world while protecting the ones he loves from dangerous opponents. However, this does not erase the fact that he was one of the most immature characters in anime when he was first introduced.
Before the Versus Momoshiki Arc, Boruto was a brat through and through. He did not acknowledge Naruto's work as the Hokage, nor did he appreciate him as a father. This stirred the entire Naruto fanbase into a frenzy. Everybody at the time hated Boruto and thought he was the worst character of all time.
9) Neito Monoma (My Hero Academia)
Monoma Neito is not a bad character, but the way he acts when talking to Class 1-A is incredibly immature. Whenever he encounters a student in Class 1-A, he always talks down to them to make himself and Class 1-B seem superior.
Despite this, he can be mature when he needs to. If someone needs his help with something meaningful, he will try his best to assist them regardless of the class.
8) Haruhi Suzumiya (The Melancholy of Haruhi Suzumiya)
Haruhi Suzumiya is the titular protagonist and unsuspecting god of the Haruhi Suzumiya franchise. Despite her godly powers, Haruhi is as human as they come, including her flaws.
She is driven to live an extraordinary life and hates boredom. Haruhi is incredibly bossy and always wants to be in charge of all the SOS Brigade's activities. Whenever something does not reach her high entertainment expectations, she will lash out at everyone around her. This makes her incredibly immature overall, but there are also moments where she shows signs of maturity, usually after Kyon gives her a scolding.
7) Chocho Akimichi (Boruto: Naruto Next Generations)
Cho-Cho Akimichi is a powerful shinobi. She can use the Akimichi Clan's Butterfly Mode beautifully and can inflict massive damage on her opponents. However, she is not that mature.
Cho-Cho constantly complains in the Boruto anime. Whenever she runs out of her favorite chips brand, she makes sure everyone knows about it and annoys everyone. She even has a steady base of haters as many fans despise Cho-cho's immature and childish behavior. Like Boruto, however, she has shown moments of maturity and has a lot of room for character growth.
6) Minoru Mineta (My Hero Academia)
Minoru Mineta is easily one of the most hated anime characters. Many My Hero Academia fans hate how he constantly harasses the series' female characters and never shows any remorse. Despite the few moments of maturity that he showed (like during his exam with Hanta Sero), he seems to be unredeemable. If he were to get a redemption arc, it would be long before everyone started to enjoy his sexist character.
5) Emperor Pilaf (Dragon Ball)
Ever since his introduction in the original Dragon Ball anime as one of the first villains, Emperor Pilaf has acted immaturely. He always acted to fulfill his self-interest, and whenever Goku and his friends defeated him, he would throw a tantrum. He would whine and cry endlessly until he got what he wanted. There were times when even Mai and Shu, his most loyal lackeys, got fed up with him.
4) Majin Buu (Dragon Ball Z)
Majin Buu is a very immature character, but not necessarily in the wrong way. He constantly acts like a child, and many times it is cute and comedic, but his immaturity can also cause significant problems for everyone.
Buu refused to share pudding with celestial beings Beerus and Whis. In fact, when they asked for the pudding, Buu proceeded to eat them all in front of the two celestial beings. This angered Beerus to the point where he wanted to destroy Earth. Majin Buu risked the safety of Earth over pudding cups! Of course, Beerus must take some blame in this situation as well.
3) Malty Melromarc (Rising of the Shield Hero)
Since the beginning of the series, Malty has always been manipulative and conniving. Although she acted friendly and became friends with Naofumi, she only did that to ruin his life quickly.
She is used to getting what she wants, and when she does not get it, she throws a tantrum. She almost wholly ruined Naofumi's life by making false accusations against him, but the truth was revealed, and she got her punishment in the funniest Shield Hero scene yet.
2) Milluki Zoldyck (Hunter x Hunter)
Milluki Zoldyck is one of the most hated members of the Zoldyck Family. In the Hunter x Hunter anime, Milluki is shown complaining to Silva for money so he can buy a copy of Greed Island. Despite being an adult, whenever Milluki does not get what he wants, he will throw a tantrum. This typically involves directing his unjust anger towards someone completely innocent and making their life miserable.
1) Mahito (Jujutsu Kaisen)
Mahito is one of the main antagonists of the Jujutsu Kaisen series. He acts like a complete child and does whatever he wants, even if that includes killing innocent people. Whenever he does not get to kill someone, he gets upset and wants to kill more people. He has no sense of morality and always makes trouble for the Jujutsu sorcerers.