In the anime, the ending takes care of Hao once and for all. He's become too damaged by his hatred, and his Reishi abilities have grown so strong that he can no longer control them. Once he becomes the Shaman King, Yoh, together with the power of other shamans from around the world, kills him once and for all.

How does Shaman King anime end?

The 2021 Shaman King anime series will adapt Takei's "perfect edition" of his manga, including its "true ending." ... The 2001 anime finished long before Takei had completed the manga, and it ended after one final battle between Yoh and Hao led to the latter's demise and brought a halt to the Shaman King tournament.

What happened to Hao at the end of Shaman King?

But instead of winning the tournament while he had the Great Spirit like in the manga series, Hao was ultimately killed by Yoh who had received helping power from shamans around the world, by forming a new Giant O.S. with which, Yoh would cut both Hao and the Spirit of Fire in half in the end.