"Going for walks at night as a hobby, this Oni Yo-kai sometimes even goes for a walk as nothing but a head. They hate being seen by humans, and since they take the eyeballs of those that see them, lay down on the ground if you happen to encounter them."
Yagyou is a fair-sized humanoid Yo-kai with clay-colored skin, a visible pointy ear and a sole visible sharp teal right eye, with the left one covered by an eye-patch. He has magenta-colored hair with two black horns sticking out, and a cloudy-looking scarf, teal in color. he wears a samurai-like attire with long clay-brown sleeves and a darker brown-colored layer of clothing above, a yellow sash on his waist, as well as two-teeth geta sandals with white tabi. he carries a fairly big golden curved sword with a green handle.
It is also worth noting that Yagyou's head can freely detach from his body.
Bounces some of the damage taken back to the enemy.
In Yo-kai Watch 3, during the first "ENMA NOTE" quest, Yagyo, alongside a group of rebel yo-kai, attempt to kill Lord Enma with the use of the Enma Note, this is clearly a parody to the acclaimed series Death Note. Notice that the 3 yo-kai involved all make a reference to the protagonist of said series (Yagyo having the power to see a yo-kai's true name with his evil eye, Inugami standing as the Shinigami, and Kirameki porting "Kira" in his name, which is a term used to refer to those who use the death note).
Yagyou is based in Yagyū Jūbei Mitsuyoshi (Japanese: 柳生 十兵衞 三厳,Yagyū Jūbei Mitsuyoshi), one of the most famous samurai figures in Japan's feudal era. He was often depicted using only one eye as the other is covered in an eyepatch, similar to Yagyou.
Folklore-wise, Yagyou is based on both the Nukekubi (Japanese: ぬけ首,Nukekubi), a type of Rokurokubi (Lady Longnek#Origin) that instead have no neck and the heads can move independently from the body at night, and Yagyou-san (Japanese: 夜行さん,Yagyō-san), a cycloptid youkai resembling an oni that hails from the Tokushima prefecture. He appears on a headless horse on very specific dates. Those who encounter this youkai on these nights experience getting bodily thrown aside or getting hit by his steed. To avoid this, one should put sandals on your head and lie down on the ground.