In Japanese anime, most heroes are written to be as likable as possible. Since they are supposed to be the audience's portal into the universe, a great number of noble or sympathetic qualities are always desirable. However, there are a handful of heroes who fall short of the mark.
Whether due to poor attitudes, lackluster development, or even unfortunate circumstances, these individuals have lost the interest and respect of viewers. By identifying them, it becomes easier to gauge the ways they have fallen short and how future heroes might avoid making the same mistakes.
Update on May 17th, 2023 by Louis Kemner: nearly all anime series aim to create likable, respectable heroes whom fans may cheer on and sympathize with, with classic examples ranging from Naruto Uzumaki to Tanjiro Kamado to Saitama the caped baldy. Then again, some anime protagonists and supporting heroes have no fans at all, sometimes because they were designed badly or because fans were actually never meant to like them. Such characters are heroes in name only, and no anime fan will cheer them on when the fighting starts.
15 Knov (Hunter X Hunter)
Knov and Morel were two of the finest adventurers in the Hunter's Association. Netero brought them with him in order to investigate the growing chimera ant crisis. But despite being handpicked by Netero himself, Knov immediately wilted at the first sign of trouble.
Encountering Neferpitou took such a high mental toll on Knov that his body aged fifty years, rendering him no longer able to fight. Unfortunately, Knov's personality wasn't developed enough for fans to feel sympathetic to his struggles and collapse.
14 Armin Arlert (Attack On Titan)
Initially, Armin Arlert was a bright young man who helped to lead the Scouts against marauding Titans in Attack on Titan. However, his characterization declined after liberating Paradis and achieving his goal of finding the sea.
Ever since, Armin's entire personality has been to complain about Eren and provide a moral contrast to other characters. This is particularly ironic since Armin himself has not been portrayed as a particularly upstanding person. For example, he told Bertholdt that Annie was being tortured just to throw him off in a fight.
13 Pannacotta Fugo (JoJo's Bizarre Adventure)
Fugo was the only JoBro to completely abandon his friends in JoJo's Bizarre Adventure. After uncovering their intentions to betray Diavolo, he left Team Bucciarati and never looked back. This is particularly egregious when considering the close relationship Fugo formed with Narancia as teacher and student.
Factoring in his poor performance against Zucchero, this meant that Fugo only took part in a single real fight before being retired from the series. It is a particular shame due to the potential of his poisonous Stand, Purple Haze. Should Fugo have stayed loyal to the team, he may have even posed a threat to Diavolo himself.
12 Neito Monoma (My Hero Academia)
There isn't much to like about Neito Monoma, a student from class 1-B. He is a braggart obsessed with defeating Class 1-A, often going out of his way to disparage them even when it is not appropriate.
To make matters worse, Neito's only Quirk is to imitate the abilities of others. As a result, he has an incredibly situational power that may prove disastrous if it fell into the wrong hands. Irresponsible and shortsighted, Neito must grow as a person if he ever hopes to become a hero in My Hero Academia's world.
11 Ikkaku Madarame (Bleach)
Ikkaku Madarame of Squad 11 was introduced as a minor antagonist in Bleach's famed Soul Society story arc. He had a strongly defined sense of honor and believed in luck, though he did lose to Ichigo Kurosaki in their first and only duel.
Ikkaku later became a peripheral ally of Ichigo's, but he was never compelling. The problem is that Ikkaku is too stubborn for his own good, foolishly holding back in fights so he can mimic his Captain, Kenpachi Zaraki. He felt like a failed hero with nonsensical ideals, so Bleach fans never warmed up to him.
10 Ludociel (Seven Deadly Sins)
Considering that Ludociel allied with the Seven Deadly Sins and even gave his life to their cause, he can ultimately be considered a hero. Regardless, his radical ideas make him extremely contentious among The Seven Deadly Sins fans.
Blindly devoted to the Supreme Deity, Ludociel sought the extinction of the entire demon race - Meliodas included. Worse yet, he manipulated humans into furthering his cause through an ability called "Fraudulent Light." Though claiming it empowered them, Ludociel actually just took away his minions' ability to respect their bodies' limits.
9 Sakura Haruno (Naruto)
Sakura Haruno's official goal was to stay relevant to her peers in Team 7 in Naruto. However, despite the training she underwent with Lady Tsunade, she could never even come remotely close to them. Worse yet, Sakura's obsession with redeeming Sasuke eclipsed Naruto's.
In addition to turning Konoha 11 against her, it also nearly got Sakura killed on multiple occasions. Though progressing since the original series, Sakura's belligerent attitude and petty obsessions demonstrated limited overall character growth.
8 Squard (One Piece)
Squard was one of many captains under Whitebeard's command in One Piece. Having previously been warned by Akainu, he stabbed the emperor in the middle of the Marineford invasion. There were many reasons why Squard's plan didn't make sense.
Not only was Akainu extremely unreliable as a marine admiral, but attacking Whitebeard in the middle of a war put his own crew in even greater danger. Despite his shortcomings, Squard isn't a bad person. Once he realized the extent of his error, he apologized to Whitebeard and begged for forgiveness. Whether deserving or not, Whitebeard embraced him as a son.
7 Motoyasu (The Rising Of The Shield Hero)
Motoyasu was a disaster for the people of Melromarc. In addition to furthering the goals of its treacherous pope, he also exacerbated the divide between Naofumi and the rest of the kingdom over a petty grudge. Gullible and stubborn, he never paused to question the legitimacy of Malty's accusations.
Despite this, Motoyasu is still technically a hero. He helped to fight off the waves and stood against the pope after uncovering his intentions. Nonetheless, Motoyasu's miserably poor judgment makes him a greater obstacle than an ally.
6 Near (Death Note)
By himself, Near is a decent character. He has a handful of quirks, doesn't cow to danger, and regards all problems with a degree of detachment. However, the issues with his personality become clearer in the context of the complete story. Near was meant to replace L as the person who would defeat Light.
However, considering that he wasn't nearly as intelligent as his mentor, he had to refer to his predecessor's existing observations for any measure of success. Additionally, Near's personality so closely resembles L's that it becomes impossible to view him as anything but an inferior copy of a legendary character.
5 Corkus (Berserk)
Even a grim, violent franchise like Berserk will have a handful of likable characters, such as the noble lady knight Casca and her knife-throwing friend Judeau. In the Golden Age arc, such characters were pretty likable, but not Corkus.
Corkus was a soldier in the Band of the Hawk, and Berserk gave fans no reason to like him. He was petty, obnoxious, and kept picking verbal fights with Guts every chance he got. He died in the Eclipse before he could redeem himself, so he remains unlikable to this day.
4 Kelvin (Black Summoner)
Black Summoner is a short isekai anime series whose protagonist, Kelvin, feels awfully similar to plenty of other isekai leads. He is yet another dark-haired power fantasy self-insert, making him generic and forgettable at best.
Even worse, Kelvin took part in the horrible "buy a slave girl" isekai trope and didn't regret it. He knowingly paid good money to a slave trader for a half-elf slave whom he freed and made his friend, but as a whole, that act made him abhorrent, not noble.
3 Sachi Umino (A Couple Of Cuckoos)
A Couple of Cuckoos is a romantic comedy harem anime that could have been much more charming if its main characters had been written better. Protagonist Nagi Umino felt generic at best, and his foster sister Sachi quickly proved herself a bratty and unlikable tsundere.
Sachi made anime fans uncomfortable when she developed a huge crush on her foster brother and asked him to see her as a woman, and not as a sister. While she had some wholesome moments with her biological sister Erika, Sachi quickly became the series' worst character and was a chore to watch.
2 Mirai Kakehashi (Platinum End)
Overall, the Platinum End anime proved to be a poor spiritual successor to Death Note, and its protagonist Mirai Kakehashi was no exception. Among other issues, Mirai was written as a generic, unengaging dandere who had very simple goals that couldn't sustain the plot.
Mirai was never a revolting or annoying character, but he also failed to stand out or make himself interesting in any way. He also frustrated fans when he stubbornly refused to use force in his battles, even when everything was at stake.
1 Ginro (Dr. Stone)
Most characters in Dr. Stone are likable and engaging, from the cocky scientist Senku Ishigami to the tough warrior girl Kohaku to the enthusiastic Chrome and Kaseki. An exception is Ginro, who feels a little too "anime" for a smart series like this one.
Ginro has nothing to contribute to Senku's Kingdom of Science except to provide annoying comic relief that no one asked for. Dr. Stone already has enough solid comedy with its other characters - the narrative doesn't need a Jar Jar Binks-style goofball whose sole purpose is to be a class clown.