After checking out Henry Jenkins' two articles, two examples of transmediatic works immediately popped into my head!
Naruto has got to be one of the most well-known Japanese Manga / Anime series in the world. I find that the Naruto universe is a great example of transmediality.
So first we have the Naruto manga, which is the original storyline and still ongoing at this time.
The Naruto manga then branched out into an anime series called 'Naruto' which covered the first twenty-seven original manga volumes but eventually continued on into original episodes that had stand-alone plots that weren't seen in the manga itself! This is one part of transmediality - while different storylines co-existing within the Naruto universe. Also, the different storylines are told on different mediums! Print versus video animation.
When the 'Naruto' anime series ended, 'Naruto: Shippuden' entered the picture. 'Naruto: Shippuden' covers the remaining volumes of the original Naruto plot from the manga (volume twenty-eight onward). Thus the different mediums continue.
Not only that, the Naruto universe has also expanded to the following:
Films: Naruto has branched out into nine different movies along with the ongoing manga and anime series.
Spin-off manga (and anime series): Rock Lee & His Ninja Pals, consisting of prominent Naruto character Rock Lee
Original Video Animations (OVA): Naruto has spawned five different OVAs with original storylines
Video games: Many Naruto video games have been released, most of which are fighting games in which the player has control over one of a select few characters available in the game and is able to fight other characters controlled by either another player or the AI. The Naruto games are able to be played on various consoles such as Nintendo, Microsoft and Sony.
Trading card game: A collectible card game based on the Naruto series. Two players can play against each other using a customized deck of fifty cards, a game mat, a "turn marker" and a "ninja blade coin".
Though diverse and utilizing different mediums, all these different branches come together under the umbrella of the Naruto universe.
All of the above comes together to drive the success of the Naruto franchise, which I think is not only proof of a very effective marketing scheme, but also a great way to make use of transmediality.
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The Harry Potter book series is by far one of the most successful to exist, and is also the best-selling book series in history, with 450 million copies sold.
Of course the Harry Potter universe began with the books, but it quickly expanded to the following areas:
Film series: The film adaptations of the Harry Potter book series (eight in total) make up the highest-grossing film series of all time.
Games: There are eleven Harry Potter video games in total, with eight corresponding with the books and film, but three other spin-offs. Other non-interactive media games (such as board games) based on the series have also been created.
Theme park: The Wizarding World of Harry Potter is a themed area encompassing two theme parks in the Universal Orlando Resort in Florida. The themed rides mostly include re-creations of places existing in the Harry Potter universe, and allows visitors to experience firsthand being within the world of Harry Potter.
A Website: Pottermore was founded by writer J.K. Rowling as a site that focuses on the unknown and uncovered parts of the book series and allows users to read the story in an interactive manner.
Besides the above, the creator of Harry Potter, J.K. Rowling, has written and published many books that exist within the Harry Potter book series, such as 'Tales of Beedle the Bard' and 'Fantastic Beasts and Where To Find Them'. As with the elements of transmediality, these books exist within the Harry Potter universe, but provide many different storylines and plots. Not only that, it adds to the interactive factor as readers and viewers of the book and movie series are allowed to read firsthand what the characters are supposedly reading themselves.
Recently a movie adaptation of 'Fantastic Beasts and Where To Find Them' has been announced, with J.K. Rowling actively involved. The main character Newt Scamander is one that exists within the Harry Potter universe, but at a different timeline as the usual characters. The film is said to be set 70 years before the original story takes place.
This is yet another way that Harry Potter harnesses the power of transmediality! A whole new story explored across different mediums.
Harry Potter's use of transmediality makes way for a complete reader, viewer and user experience that brings audiences deeper into its' fictional world.