Youmu

Youmu (妖夢, lit., "catastrophic illusion") are strange creatures that roam the human world. They come in all sorts of shapes and forms, and their origins are currently a mystery. Some Youmu have an appetite for human flesh and are extremely hostile. For this reason, these creatures are a constant target by Spirit World Warriors.

Characteristics

A youmu stone dropped from a felled youmu.

Youmu vastly differ in appearance, with forms similar to that of animals or non-living objects. The similarity among all youmu is their tendency to manifest an ore-like stone that contains the powers of that youmu when slain. This stone is sought after due to the value appraisers give to these stones.

Humans normally do not possess the ability to see youmu, and can only be seen by Spirit World Warriors and other youmu. However, interactions between youmu and humans are a constant source of concern amongst Spirit World Warriors due to a youmu's tendency to possess a human and act towards them with hostility. In the light novels, the issue of discrimination against youmu extends to half-youmu and Spirit World Warriors with youmu-like abilities (i.e., the Kuriyama clan, in which Mirai Kuriyama belongs to).

List of Youmu

Known Non-Hostile Youmu

Name	Characteristics	Occupation/s	Status
Ai Shindou	Has a human and animal (two-tailed Scottish fold) form	High school student, assistant to Ayaka	Alive
Ayaka Shindou	Has a human and animal (nine-tailed fox) form	Spirit world warrior, appraiser, owner of a traditional sweets shop (photo studio in the anime)	Alive
Akihito's Father	Immortal youmu	—	Unknown
Yakiimo	Rodent-like appearance with a round body	Mitsuki Nase's pet and fighting companion	Alive

Known Hostile Youmu

Name	Debut	Abilities	Value (in Yen)	Status
"Ogre"	Ep 1	None	26,000	Killed by Shizuku Ninomiya
"Bandage Ghost"	Ep 1	Bandage manipulation, phasing through solid objects	1,000	Killed by Mirai Kuriyama
Hollow Shadow	Ep 2 (mentioned), Ep 4 (appearance)	Unknown; is said to be a powerful youmu that has a main body and can create labyrinths to trap people	???	Killed by Mirai Kuriyama
"Slit-mouthed goblin"	Ep 3	Small youmu with a vertical mouth filled with pointy teeth	10,000	Killed by Mitsuki Nase
"Wolves"	Ep 4	Physical appearance and fighting style reminiscent of wolves	???	Several killed by Hiroomi Nase
"Fruit-Type Youmu"	Ep 6		At least 500,000	Alive
"Candy Stick"	Ep 7	Possession of humans (not unique); other abilities unknown	???	Killed by Mirai Kuriyama
Beyond the Boundary			???	Alive