Spirit World Warrior

Spirit World Warrior (異界士 Ikaishi) are people whose job it is to subdue the Youmu. Their abilities are passed on by blood.

Society
The Spirit World Warrior Society acts as the government for the Spirit World: watching over important events, registering new Spirit World Warriors, making and enforcing laws, and maintaining records of Youmu.

Known positions
Appraisers are people officially recognized by the Spirit World Warrior Society to accept Youmu stones and designate monetary values to them based on the type of Youmu slain. Due to this ability, Appraisers are often highly sought after by Spirit World Warriors wishing to earn an income from defeating Youmu in battle.

One known method of appraising a Youmu stone is by careful observation of the stone against an array of spells that an Appraiser sets up, it's here they determine the value of the stone depending on the Youmu source and various other factors. According to Ayaka Shindou, a known Appraiser, the changes in levels of aggression does not affect the value of the Youmu — a fact that annoys Spirit World Warriors who're unfortunate enough to encounter Youmu which are more aggressive than normal.