Shaman King by Hiroyuki Takei was one of the first titles released by Viz Media's American publication of Shonen Jump. In the early 2000s, Shaman King was one of the first major shonen action manga that was readily available for a voracious audience of pre-teen and teen readers. Over the years, Shaman King faded from mainstream popularity, especially compared to the rising popularity of the Big Three of Shonen Jump, as well as other major anime and manga titles over the last several years.
Regardless, Shaman King's license has fallen through, meaning you can't legally buy a volume of the manga outside of a used bookstore. The reasons why are incredibly frustrating to both potential new readers and old fans alike.
The Original Publication
Shaman King was originally published in Shueisha's Weekly Shonen Jump starting in 1998. However, the manga abruptly came to an end in 2004. The lack of a real ending left a bad taste in fan's mouths. A reprinting of the manga between 2008 to 2009 came with a newly written final chapter that brought a more conclusive end to the series.
Many suspected that Shueisha canceled Shaman King because it wasn't popular, but it was clearly popular enough to motivate the manga's republishing and ultimate new ending -- as well as the multiple spin-offs Shueisha would later publish. The real reason Shaman King ended was because of Takei's fatigue. He felt that, by bending to the requests of fans to add more traditional shonen elements, Shaman King had lost its originality, growing increasingly generic. However, he also returned in part to finish the manga because he didn't want to let his fans down. All of this seems to indicate that Shaman King's popularity was never a factor in its cancellation.
Shaman King was translated into English in Viz Media's Shonen Jump starting in 2003, while 4Kids's dub of the anime aired the same year. The manga, published alongside the uncut publication of Yu-Gi-Oh, Naruto, and Dragon Ball, proved tremendously successful, heralding in a large fan following in the states. Viz would publish the entire manga in the West and distribute it for many years.
Spin-Off Shenanigans
The first spin-off was a five-chapter story published after Shaman King's abrupt initial conclusion but before its final chapter. Shaman King: Poem of Funbari focuses on Yoh and Anna's son, Hana Asakura, and his family's quest to find the Five Elemental Warriors for a special demand. The manga was created after a fan campaign for Shueisha to revive the manga, which eventually led to the final chapter and more spin-offs. This was also the only spin-off to be licensed by Viz Media.
After the release of the final chapter, two more spin-off manga were published by Shueisha. In 2011, a series of one-shot "Zero stories" focused on character backstories were published in Shueisha's Jump X mangazine. In 2012, a second spin-off series, Shaman King: Flowers, focused on Hana Asakura's development and experiences as a shaman. Both Shaman King: Zero and Shaman King: Flowers were written and illustrated by Takei and finished publication when Jump X folded in 2014.
In 2018, the next two spin-off manga for Shaman King -- Shaman King: The Super Star and Shaman King: Red Crimson -- were published in rival company Kodansha's Shonen Magazine Edge. The original publisher Shueisha lost the license in 2017 to Kodansha. While Viz initially assured fans that this didn't affect their license of the series, months later, Viz Media's license expired and Kodansha chose not to renew it. Kodansha now owns the international license to Shaman King.
Many fans expected Kodansha did this so their American branch, Kodansha USA, could distribute the manga rather than Viz. Kodansha USA had reprinted several manga whose licenses had slipped in the USA before, such as Sailor Moon, whose license expired in the mid-2000s. However, as of 2020, no motion has been made to republish the book in America. Kodansha owns the trademark of Shaman King in America but has done nothing with the license. Hopefully, Kodansha can bring Shaman King back from the dead so it can experience a second life on American shelves.