Truly a horrorfying monster matched only by its master in terms of speed, power, and deadlyness. Even its flames place horror into its enemies as its flames both consumeflesh,blood and soul! The Spirit of Fire Was created a long time ago no one really knows when only the Hapachi tribe does. The Spirit of Fire is considered a Godairai class spirit which translates to a God Class level spirit. According to legends the Spirit was created by the Hapachi tribe using the Great Spirits power. In adition to the Spirit of Fire the Hapachi tribe also created four other spirits. They were known as the Spirit of Water, Spirit of Earth, Spirit of Wind, Spirit of Thunder. Together all five of them served as a symbol of hope for the Hapachi tribe. That was until 500 years ago. When a man by the name of Hao (which is later explained that he is Hao's reincarnation) stole the Spirit of fire for himself and fled the village seeking to find worthy shamans for his shaman only kingdom. Luckily when the Shaman King tournament took place one shaman was able to put a stop to Hao's madness. It is believed that shaman was of the Asakura clan bloodline. Because of the damage done by Hao the Hapachi Tribe feared that any other shaman would attempt to steal and abuse the power given by the elemental spirits because of this fear the Hapachi tribe seal off the remaining spirits at the bottom of the great spirit in the four corners of hell. What seperates the Spirit of Fire from ordinary spirits and even god class spirits is its ability to evolve. It evolves in a horrorific manner by consuming living souls, spirits. Using his intellect Hao created not only an effective medium but also one of the fastest, being that The Spirit of Fire's medium is oxygen itself. It is never revealed what medium it takes on when changing elements via the ying yang jutsu. The spirit can also manifest itself by turning into a form of spirit armor which Hao himself refers to ask Black Fowl.
In this form Hao's speed tripples and is granted far more offense/defense Hao is even granted a jetpack like ability through this "Spirit Armor", but the real advantage to using this technique is that it requires less furyoku to use. In the ANIME Hao shows his mastery over the Spirit of Fire by compressing the spirits form into a blade. Because the spirits power is now compresssed it is much smaller but what it looses in power it more then makes up for in strength as its blade density as that of the Spirit of Fire in its entire form