The manga and anime series Shaman King features several characters created by Hiroyuki Takei. As a result of being focused on shamanism the series' cast is divided between humans and spirits, the latter not being able to go the afterlife due to their alliance with the former.
The series primarily focuses on a teenager named Yoh Asakura, who reveals to his classmate Manta Oyamada that he is a shaman when fighting a group delinquents led by Ryu. Wishing to lead a peaceful life, Yoh has been training from an early age to become the titular "Shaman King", who will be able to change the world according to his will. During Yoh's training, Manta meets Yoh's demanding fiancée, Anna Kyoyama and Yoh's spirit partner, the samurai Amidamaru. In his journey to become Shaman King, Yoh also meets with a number of rival shamans who seek to become Shaman King for their own reasons and visions of the future, some who become his allies and others who become his enemies. The series' sequel, Shaman King Flowers, deals with Yoh's son, Hana Asakura, on his development as a shaman.
In terms of developing Shaman King, Takei has noted that he creates the characters first and develops the story around them. The originality of characters was emphasized so that they stand out, which may include incorporating designs that appeal to Takei; in particular, the fox and raccoon-dog duo of Konchi and Ponchi were inspired by Ren and Stimpy.
For Takei, the female lead Anna Kyoyama was regarded as the easiest character to draw and the protagonist Yoh Asakura was the hardest; Takei explained that it was difficult to develop Yoh's character because of the criteria set by Weekly Shōnen Jump. The engagement between Yoh and Anna being introduced at the beginning of the story has been regarded as unusual for a shonen manga for its maturity and partly reflects Takei's own personal experience, but it still an ideal relationship.
A number of characters in Shaman King previously appeared in Takei's preceding work, Butsu Zone, though Takei regards both Shaman King and Butsu Zone as occurring in different worlds akin to Osamu Tezuka's Star System. Notably, Anna Kyoyama was based on the lead character in his debut one-shot, Itako no Anna, who also inspired a character with a similar design and background in Butsu Zone; Takei has remarked that Anna is his signature character. The members from the Gandhara faction, particularly its leader Sati Saigan, also appear to be heavily based on main characters from Butsu Zone.