Fudou Myouou is the Japanese name for Acala, one of the Five Wisdom Kings of Vajrayana Buddhism. Acala means "Immovable," meaning how Acala is not moved by temptations of worldly desires. In Japan, Fudou Myouou means the "Immovable Wisdom King." He is the wrathful emanation of the Cosmic Buddha, Dainichi Nyorai, and he frightens people into accepting his teachings.
In Japan, Fudou Myouou was also a protector of mountain spirits and mountain hermits and is also revered as a god of fire. He wields the Kurikara (the evil-subduing sword) in his right hand, and a rope, which he uses to bind and capture evildoers, in his left. The flames in the background represent the purification of the mind, and some say they originated from the vomit of the Karura. Some say that Fudo is the god Shiva.
"Origin: India. The chief of the Five Wisdom Kings. He wields a sword in his right hand and a lasso in his left. Instead of an aureole, flames cover his back. Of his eight servants, Kongara and Seitaka are often depicted serving him."
—Shin Megami Tensei A-Mode DDS dictionary
Devil Summoner: Soul Hackers
Fudou Myouou is referenced through the spell "Kurikara Kokuryu," which unleashes his power to inflict multiple fire attacks on all front row enemies.