Some of the most acclaimed and successful anime series are adaptations of already established works in other mediums. The most popular titles are typically manga adaptations, though stories sourced from visual or light novels are also incredibly common. High-quality video game adaptations or spin-offs have also increased in quantity in recent years.
These titles come with built-in fan bases who become excited to experience their favorite stories put to animation,and when they’re done well, those fan bases will greatly expand. Unfortunately, however, not every adaptation is entirely faithful, and these 10 became infamous for not doing their source material justice.
10Record of Ragnarok
Animated by Graphinica, Yumeta Company, and Maru Animation, Based on the Manga by Shinya Umemura, Takumi Fukui, and Azychika
Record of Ragnarokarrived on the scene in 2021 and made some noise early on, being featured in Netflix’s lineup of exclusive anime before the streaming service began taking on more titles every season. As a combat-focused dark fantasy manga,Record of Ragnarokpromised the sort of action that fans of the genre would adore, but the anime ultimately failed to deliver.
Rather than straying from its source material in major ways, like some other titles infamously have,Record of Ragnarokfailed to capture the intense, flashy action fans had hoped to find—often featuring uninspired, stilted, and entirely unimpressive animation. However, the series can always turn it around inthe recently announced third season.
9The Beginning After the End
Animated by Studio A-Cat, Based on the Novel Series and Webtoon by TurtleMe and Fukyuki23
The Beginning After the Endwas one of the latest in a string of novels and webtoons to receive a highly anticipated anime adaptation in 2025. Following the sort of hype generated bySolo Leveling, one of its contemporaries, fans had hoped the series would be the next to break through and impress the general anime fan.
Unfortunately, Studio A-Cat’s adaptation failed to impress not only the general anime fan, but also fans of its source material.The Beginning After the Endwas heavily criticized for its lackluster visuals and poor pacing, and became one of the most disappointing releases of the season.There’s time for the studio to turn it around in season two, but damage has certainly already been done.
8The God of High School
Animated by MAPPA, Based on the Manhwa by Yongje Park
Fans ofThe God of High School, another incredibly popular manhwa series originating from South Korea, became ecstatic upon learning the series would be receiving an adaptation bythe illustrious Studio MAPPA. The series, which featured its own stylish brand of combat, seemed perfect for a studio known for its prolific action releases.
Unfortunately, MAPPA just couldn’t come through as fans had hoped, delivering an adaptation that, while looking pretty, was plagued with pacing issues. Also cutting some content from its source material,The God of High Schoolflopped with fans, and no word of a follow-up has been given since its ending in 2020.
7Berserk (2016)
Animated by GEMBA, Millepensee, and Liden Films
Berserkis one of the most influential and successful manga series of all time, but apart from the Golden Age arc, which was turned into both a series and film trilogy,it wasn’t ever adapted to completion. So when 2016’sBerserkwas announced to continue the series after its most iconic section, fans were beyond excited.
Unfortunately, what they got wasn’t exactly what they wanted. 2016’sBerserkdidn’t take liberties with the manga, but rather failed to capture any of the magic of Kentaro Miura’s masterful artwork. The series' mixed 2D-3D visuals didn’t sit well with fans, and it went down as one of the most disappointing adaptations in anime history.
6Soul Eater
Animated by Bones, Based on the Manga by Atsushi Ohkubo
Soul Eaterwas immensely popular throughout its original run more than 15 years ago, and for good reason. The series featured its own distinct style and aesthetic, and mixed high-energy action into a unique premise about humans who can transform into weapons. Over its first 30 or so episodes, the anime was largely faithful, but that all changed in its second half.
Fans felt betrayed by what they had seen, and it was made only worse by the fact that Bones rectified another of their original endings that same year inFullmetal Alchemist: Brotherhood.
More original content was injected into the series as time went on, and by the time it reached its finale, studio Bones’Soul Eaterventured off into its own entirely original content.Fans felt betrayed by what they had seen, and it was made only worse by the fact that Bones rectified another of their original endings that same year inFullmetal Alchemist: Brotherhood.
5Deadman Wonderland
Animated by Manglobe, Based on the Manga by Jinsei Kataoka and Kazuma Kondou
Deadman Wonderlanddrew quite a few eyes as a manga series, and its anime adaptation by Manglobe, the studio behind iconic titles likeSamurai ChamplooandErgo Proxy, became highly anticipated before its release.As a more mature, dystopian shōnen series, fans were excited to sink their teeth into something on the grittier side.
However, the adaptation would attempt to stuff 13 volumes of manga into just 12 episodes, and the series featured incredibly rushed pacing that took away from the complex themes and character developmentDeadman Wonderlandplayed with. A series that was known for its blend of psychological horror and action just fell flat on screens.
4Uzumaki
Animated by Fugaku and Akastuki, Based on the Manga by Junji Ito
Junji Ito is one of the most successful and recognizable manga artists on the planet, and his unique brand of horror has shocked and scared readers for decades. However, very few anime adaptations of his work had ever gone well, so when fans got word of a faithfulUzumakiadaptation in the works, they held their breath in hopes it would turn out to be high quality.
Unfortunately, they were disappointed once more whenUzumakiarrived and dropped the ball hard in its second episode. The series' visual quality plummeted and drew far more laughs than it did screams, while the story itself felt incredibly rushed over the course of four episodes. It seems fans will have tocontinue waiting for their quality Junji Ito anime adaptation.
3The Promised Neverland
Animated by CloverWorks, Based on the Manga by Kaiu Shirai and Posuka Demizu
The Promised Nevelandis one ofthe most disappointing anime series ever. After an incredibly successful and impressive first season, which garnered quite a bit of fanfare as one of Netflix’s earlier featured anime titles, the series returned with a second season most fans pretend never happened at all.
The Promised Neverland’s second season attempted to rush through far too much content and bring the series to a close, rather than stretching the source material over the course of three seasons.
What resulted was a largely incoherent mess that omitted one of manga’s most popular arcs, and no matter how hard fans attempt to pretend it didn’t exist, none will be able to forget their disappointment.
2Tokyo Ghoul
Animated by Pierrot, Based on the Manga by Sui Ishida
Tokyo Ghoulburst onto the scene in 2014 and appeared poised to join the likes ofAttack on Titanasone of anime’s most popular and exciting new titles. Though the first season featured some differences from the manga, it was received well, and fans around the world couldn’t wait to watch its follow-up the next year.
For some unknown reason, Studio Pierrot made the decision to move away from the source material entirely, and delivered an anime-original second season. When the sequel series,Tokyo Ghoul: re,arrived, it built upon events that took place in the manga, leaving fans confused about what exactly they were experiencing.
Over a decade on fromTokyo Ghoul’s premiere, fans are still calling for the series to be revisited and done right.
1Umineko When They Cry
Animated by Studio Deen, Based on the Visual Novel by Ryukishi07
Umineko When They Crymight just be the most popular and acclaimed visual novel ever. Written by Ryukishi07, the mind behind another beloved multimedia franchise,Higurashi When They Cry, the visual novel is known for its complex characters and tangled mysteries, which unfold over quite a lengthy experience.
Unfortunately, the anime by Studio Deen was entirely unequipped to deal with that length. With only 26 episodes to work with, the adaptation failed to win over the visual novel’s massive fan base.
2009’sUmineko When They Crydelivered an incomplete story with rushed pacing that was forced to ignore countless major plot points in order to squeeze hours of storytelling into a compact product, and fans were not happy about it.
Umineko: When They Cry
Cast
The annual family conference will discuss inheritance due to the head’s poor health, but Ushiromiya Kinzo is focused on reviving his love, Beatrice. Immersed in black magic, he plans a ceremony to bring her back during the family gathering.
