Lastly, he commented about the anime only material that the 2001 anime had later, in which he stated that it wasn't something he did on his own accord, but it was a request from Shaman King's then publisher Shueisha. He also mentioned that this case is similar with the 2003 Fullmetal Alchemist anime, which he also directed and emphasized that he wasn't simply changing the story to suit his own whims.
[Source: Anime News Network]