The Momunofu are the followers and guardians of the ancient Japanese god Arahabaki, and a type of Shikigami. Some believed that they were the prototype and cognate of Momotaro and Mononofu (same as Samurai; written in kanji as 武士).
"Origin: Japan. A clan of Shikigami attending to Arahabaki. They live by the sword and are Arahabaki's bodyguards. Their name is supposedly the source of the word 'mononofu' (samurai). They are also said to be the origin of the Momotaro legend."
—Shin Megami Tensei A-Mode DDS Dictionary
Shin Megami Tensei III: Nocturne
"A god of war in ancient Japanese mythology. He is a subordinate of another ancient god, Arahabaki. It is said that 'Momotaro', a legendary hero, was based off of him."
"A war god of ancient Japan. One of Arahabaki's subordinates. He is said to be the model for the fairy tale hero Momotaro, and is the origin for the word "momunofu," Japanese for "warrior.""
—Shin Megami Tensei IV Apocalypse compendium
Momunofu can be found inside the Toyosu Shelter and the Konganji Passage in Ginza. He can teach the Charge, Oni-Kagura and Heat Wave skills through his Demon Whisper. Momunofu benefits from learning Physical attacks. He will be at a disadvantage against other demons that use status ailment skills, as he is weak to most of the ailments.
Devil Survivor 2 Record Breaker
"War gods from ancient Japanese mythology. They were subordinate to the primeval god Arahabaki. Said to be the model for the legendary hero "Momotaro". Later, the warrior name "Mononofu" was derived from it. For the Mononobe clan during the Kofun era, divine children born in response to prayer were also called Momunofu."
"A war god in ancient Japanese lore and one of Arahabaki's subordinates. The character Momotaro from old fairytale is said to be modeled after him, and his name is the origin for the word "mononofu" the Japanese word for "warrior." The ancient Mononobe warrior clan would call their gifted children Momunofu in his name."