Shonen is a massive category, filled with countless titles, and it’s home to some of the most popular and influential series in anime history. With so many incredible franchises under its belt, it almost feels like every shonen series is an instant hit. However, plenty of titles have disappointed fans over the years.
Sometimes, a new series is hyped up so much that it fails to meet expectations. Other times, a popular series gets a poor anime adaptation that leaves the audience underwhelmed. For these reasons and many others, shonen anime aren’t always a smashing success with fans.
10 Soul Eater's Ending Is Confusing & Strays Far From The Manga
Soul Eater is one of the most unique shonen series to come out of the 2000s. Nevertheless, it's easily one of the most disappointing. It started out strong with its first season, but things started to go wrong soon after. Because the Soul Eater manga was still ongoing at the time, the anime ended up creating its own anime-only ending, and fans were not happy with it at all.
It took the series in a very confusing direction and strayed far from the source material, leaving out key moments that were critical for character growth and progression in the plot. Nowadays, the Soul Eater anime is seen as a complete disappointment, and many long for a reboot that does it justice.
9 Future Diary Turned Out To Be An Overly Edgy Story With A Messy Plot
The hype was real when Future Diary was first released, and many fans were expecting it to be the next great shonen series. Unfortunately, the hype train crashed and burned very quickly with this series, thanks to the messy and ridiculous plot, unlikable characters, and overall edginess of the story.
In fact, Future Diary became infamous for being edgy, and most can't help but cringe at the toxic relationship between Yukiteru and his yandere girlfriend, Yuno Gasai. For a series with so much promise, it really disappointed fans in almost every way and is now considered one of the worst modern shonen anime.
8 Fullmetal Alchemist's First Adaptation Doesn't Give Fans The Happy Ending They Want
By now, the first anime adaptation of Fullmetal Alchemist is infamous for how disappointing it is. Though many admit it nails the feel of the series, fans just can't get behind the depressing anime-only ending and consider it too far removed from the manga.
When the manga's iconic ending came out, this only strengthened the disappointment fans felt toward the anime. Luckily, the series was rebooted, and this time, it followed the manga faithfully, from beginning to end. With the release of Fullmetal Alchemist Brotherhood, fans finally got the happy ending they longed for.
7 Seven Deadly Sins Is Ruined By Low-Quality Animation
Seven Deadly Sins is a series that fans either love or hate. Many adore the manga and consider it a masterpiece of modern shonen, filled with depth and lovable characters. However, many fans have been unable to look past its tasteless fanservice and bad humor, instead seeing the series as lowbrow and crass.
No matter fans' opinions, it's clear to everyone that the Seven Deadly Sins anime is a massive disappointment, thanks to its infamously bad animation and poorly translated subtitles. Its quality dips so low at times that it completely ruins some of the most iconic moments in the series, causing many long-time fans to give up on the anime adaptation.
6 Fairy Tail Is Just Another Generic Shonen Series
There was once a time when Fairy Tail saw incredible popularity among shonen fans. It was a promising new series that many believed could even match up to the likes of the Big Three. However, it quickly fell off, and the hype died out entirely.
While the series has a solid storyline and likable characters, it simply failed to bring anything new to the table. Many felt that Fairy Tail was just a boring and generic shonen series, and even if it wasn't bad, it just wasn't good enough.
5 One-Punch Man's Second Season Fails To Live Up To The First
With its hilarious comedy mocking all the classic tropes found in a typical shonen, One-Punch Man quickly stole the hearts of fans everywhere. It was a breath of fresh air among the usual generic stories and adventures, and its first season saw amazing success.
When Season Two was announced, fans were ecstatic. But this excitement wouldn't last, as the series' continuation failed to live up to expectations. With a dip in the animation quality and a dull storyline, much of what made the series so good in the first place was lost, disappointing most fans.
4 Yashahime Gave Fans An Underwhelming Next-Generation Story
When a beloved anime series gets a "next generation" sequel, it's often hit or miss. Unfortunately for Yashahime, it's widely considered a pale imitation of the classic 2000s series. Many were excited when it was first announced, ready to finally see a continuation of Inuyasha after its conclusion over a decade ago.
But when the sequel series was released, many were unable to connect with the new girls like they could with the original cast, and much of the series was a let-down. With its poor pacing, weak characters, and bad storyline decisions, Yashahime has failed to resonate with fans like its predecessor once did.
3 The Melancholy Of Haruhi Suzumiya Made A Grave Mistake With Its "Endless Eight" Arc
Back in the 2010s, The Melancholy of Haruhi Suzumiya was one of the most popular anime around, taking the anime world by storm. But as quickly as it rose to fame, it all soon came crashing down. The series lost most of its popularity, all thanks to the infamous "Endless Eight" filler arc of Season Two.
It consists of Kyon, Haruhi, and the rest of the gang repeating the same summer vacation over and over, for a span of eight episodes. Many gave up long before this monotonous arc could end, but even those who stuck it out eventually lost interest in the series afterward. With just this one arc, the Haruhi Suzumiya empire crumbled, and just about everyone came to despise the series.
2 The Promised Neverland Ruined Its Momentum With A Horrible Second Season
The Promised Neverland saw immediate success among fans, and it was poised to be the next modern classic. However, that all changed with its disappointing second season. The series had been very faithful to the manga up until this point.
However, Season Two of The Promised Neverland suddenly took a turn for the worst. It left out many major arcs and characters, cutting out much of the lore that made the manga so beloved. Instead, it gave fans a hurried and flat conclusion that failed to satisfy fans despite its happy ending.
1 Boruto: Naruto Next Generations Fails To Live Up To Naruto's Legacy
When Naruto finally came to an end back in 2017, it was huge news. Though fans were sad to see it go, many were hyped over the oncoming sequel series, Boruto: Naruto Next Generations. The idea of the original cast settling down and starting families sounded great. Unfortunately, it failed to live up to fans' expectations.
Boruto and the gang turned out to be pretty dull compared to their parents, and they were even bratty and annoying at times. Many fans have since struggled to get invested in their story, and even the original characters have lost their former appeal. While in recent years, Boruto has started to see some improvements, many are still disappointed in the way it's played out and have all but lost interest.