Anime and manga are just so ubiquitous that whenever a new anime comes along, fans just assume that it was inspired by a Manga. But then there are many anime that are based on light novels, visual novels, video games, and even playing cards!
But then there are the times when anime is considered an original adaptation. Though this term seems like a bit of an oxymoron, an "original adaptation" isn't an adaptation of anything at all. It might inspire manga in the future, but the anime is still what came first. There are even times when the anime and manga are released simultaneously as the whole thing was planned as one big franchise. This can lead to the anime being the "original" without even being released first.
10 The Big O: The Anime Knows How To Franchise
This might be surprising since the manga actually came out a few months before the anime, but the anime was developed first during production. With the manga being developed to help promote it. Fans familiar with both seemed to have picked up on this, since the manga goes in a darker direction than the first season and seems to be more in-line with the second season.
Surprisingly, the series actually has a lot of Western influences, with the main character heavily influenced by Bruce Wayne.
9 Cowboy Bebop: The First Manga Was In Its Own Little World
While Cowboy Bebop did soon get a manga, similar to The Big O, it was also made to promote the anime. They were, more or less, released alongside each other, though sources tend to disagree on which version was actually released first. Regardless, the first manga seems to be its own continuity to the anime, with a second manga more directly connected to it.
The series also takes on a lot of genres, from western to cyberpunk. It's also especially known for its musical style and references to everything from sci-fi movies to historical figures.
8 Cute High Earth Defense Club LOVE!: The Manga Ended Up About The Villains
Magical girls are so iconic and beloved in anime, that it was about time to let boys in on the fun. Casual viewers may assume the series is technically an original parody of the genre- which is pretty accurate.
A web manga was released to promote the series, although one thing gives away the fact that it's a tie-in (rather than the original.) The manga focused on the villains. A light novel series was also released to promote the release of the anime.
7 FLCL: It All Started With An OVA
Technically starting as an OVA, this series would quickly get novel and manga adaptations. The last of which is often seen as more warped, albeit less comedic, than the original animated storyline.
While the first six episodes were released as an OVA, the later seasons saw either theatrical premieres or were released on television. In fact, the third season infamously got its start in the United States on April Fools' Day.
6 Hell Girl: This Anime Even Got A Live Drama
This horror series, in which people can damn a person immediately to hell (at the cost of being damned themselves) started with an anime series. Although a manga adaptation was released more or less around the same time, in addition to a few manga spin-offs. With the anime having a longer lead time, various characters like Hajime and Tsugumi were originally dropped in the earlier manga.
The anime also proved popular enough to inspire a live series. In fact, the titular Hell Girl is actually killed off at the end of the second series, but this had to be reversed when it was decided the anime was popular enough to have a third season.
5 I'm Gonna Be An Angel!: The Director Came Up With The Anime First
This series (based around a young girl named Noelle from a family of monsters who aspires to become an angel,) was originally envisioned by the director as an anime, although a manga adaptation came around out the same year.
Some fans suspect the series might have taken a few influences from American sitcoms, like The Munsters and The Addams Family. This is due to the fact that Noelle is the daughter of what appears to be Frankenstein's monster and a witch, with another witch for a grandmother and a vampire brother.
4 Kaleido Star: The Manga Came Out A Decade Later
This series (which revolves around a young girl who travels to the United States to become a performer,) not only started as an anime but most of its early spin-offs were animated as well. From the original video animations to an anime film.
While the series would eventually get a manga spin-off, it would come out as one of the later incarnations of the series which was a few years after the original anime. A novel adaptation was also released around the time of the manga.
3 Ojamajo Doremi: There's Even A Surprising Light Novel Series
This magical girl series (in which young girls learn to become witches,) started as an anime, lasting for different seasons. A few manga adaptations have been released and they are usually connected to each of the different series that make up the anime.
Interestingly, a few years after the anime had finished its run, the series spun-off into a long-running series of light novels. Although this time aimed towards the shonen genre. An original net animation would come out a few years later as well.
2 Princess Tutu: Ahiru's Not Even A Duck In The Manga
While technically drawing from Swan Lake and The Ugly Duckling, this anime (in which a girl named Ahiru, who is in truth a duck, must become the heroine Princess Tutu,) not only came before the manga, but it actually finished a few days after the manga even came out.
While the original anime arguably deconstructs the magical girl genre, the manga plays it slightly more straightforward. For starters, the idea of Ahiru being an actual duck, (the literal meaning of her name,) was dropped entirely.
1 Zombie Land Saga: Zombies Are Not To Be Kept Waiting
This series, in which a young girl is killed in a traffic accident (only to be revived as a zombie in order to be recruited as part of a secret zombie idol group,) also started with the anime.
A manga adaptation was released a few days after the anime premiered, as the show's second season was planned to be picked up a few years afterwards.