Stillborn Franchise / Anime & Manga

• Martian Successor Nadesico was planned to have a trilogy of movies to tie up loose ends, along with a video game to explain how things ended up that way. The Prince of Darkness bombed quite badly, and no more effort has been put into the series. A video game that covers the events between the series and The Prince of Darkness was released, but in Japan only.
• Great Dangaioh’s performance was bad enough to have the show get cancelled and leave things hanging in episode 12 (out of a planned 26). This effectively ensured that the Dangaioh series as a whole would never get a proper ending (let alone resolve the OVA's events). Creator Toshiki Hirano sealed the deal by declaring Dangaioh to be "cursed" and vowing never to work on another Dangaioh project.
• Sonic the Hedgehog: The Movie was supposed to be a full-fledged anime series, but only two episodes were released because the franchise's popularity in Japan is lower than it is elsewhere.
• Techno Police 21C from Studio Nue was going to be a TV series about a team of 3 policemen and 3 human-sized childish prototype Tin Can Robots fighting crime in the year 2001^note The concept was still fresh for late 1970s. Also of note are composer Joe Hisaishi, who would later write music for Spirited Away, Princess Mononoke, Nausicaä of the Valley of the Wind, Sonatine, Fireworks, and artist Shoji Kawamori, who would later create Macross. After some 4 years of Troubled Production they managed to make an 80-minute pilot. And repurposed it as a theatrical movie. Which wasn't very successful.
• A lot of anime ends up being this, especially when they're the adaptation of something that hasn't finished yet. People who follow anime sales invented the idea of the "Manabi Line", where a series must pass a certain amount of BD sales per volume (at least 2900 units) to warrant the hopes of getting a second season. Failing to do thus results in a stillbirth adaptation. The actual validity of the Manabi line, as well as the relative importance of BD sales of general is a topic of much debate; especially after streaming services such as Netflix and Prime Video, along with numerous other homegrown platforms have become preferred methods of viewing Anime in Japan during the late-2010s.
• Takara Tomy hyped up Pretty Rhythm by trying to promote it everywhere, stating that the anime combined many things the target audience loved such as fashion and dancing, all whilst teaching them to follow their dreams. However, not that many children played the game (in total, there were only 400,000 uses throughout its entire run) or watched the anime. Its successor PriPara eventually took up the reigns of their above statement, and ended up totally eclipsing Pretty Rhythm in popularity. After the surprise runaway success of the King of Prism films (especially since they were a spinoff of the old Pretty Rhythm series), and the Colbert Bump it gave to Rainbow Live in return, the franchise was rebranded as the Thematic "Pretty Series" and sold itself on a new experience every installment. This particular strategy was the one that ended up working in the long run.
• Kemono Friends was narrowly close to dying on birth: the original mobile game ended up being a flop, the manga's fanbase was middling, the anime was greenlit only because Kadokawa was already bound by contract to produce it, and as a result the anime was produced under a shoestring budget that didn't even reach the hundred thousand dollars it spent to make it. Its sudden and unexpected success was one of the big reasons why it was considered the big anime surprise of 2017.
• In 2014, Avex began the first series in a unisex anime franchise about dancing that aired as part of the Nichi Asa Kids' Time block, Tribe Cool Crew. The series did so well that a second installment in the franchise, Brave Beats, was created. Unfortunately, this show had such low ratings that it was Cut Short to 22 episodes.
• Under the Dog was going to be a full-fledged franchise. After two years of Troubled Production, they managed to make a 22-minute pilot that was released to middling reviews. Two years later they released an expanded version that performed better but with the people involved having moved on to other works, it's highly unlikely it will ever be revisited.
• The manga Cheat Slayer, from the writer of Kakegurui, was a revenge manga that would have revolved around a young man from a fantasy world trying to wage a personal war against a group of copyright-friendly bastardized versions of protagonists from various Isekai franchises. The manga only lasted a single chapter before it was cancelled after several manga fans and some artists accused the author of making the manga in bad faith and for making the villains too similar to their inspiration (most notably the Black Swordsman "Kilt" and a clear Expy of Aqua named Flare)—there were credible rumors that the author and publisher would have been sued for copyright infringement by other creators if it kept going. The author had to apologize and the publisher announced that new manga proposals would go through a more rigorous editorial examination to prevent something similar from ever happening again.
• Wave! Let's Go Surfing! was meant to be a multimedia project focusing on Bishōnen surfing, debuting with an anime and mobile game releasing in the early months of 2021. However, the anime recorded terrible sales^note Less than 150 combined for all three Blu-Ray volumes being sold and the mobile game shut down no less than two months after it started.

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