Other Characters/Humans

Mr. Hyoudou
Voiced by: Mitsuru Ogata (Japanese), Sonny Strait (English)

Issei Hyoudou's father and an ordinary office worker. He has unofficially adopted Asia as a second child and supports Issei's relationship with Rias. It has been shown that he is proud of his son's uprising popularity with girls, stating that he also wished to have a harem of his own when he was Issei's age.

Mrs. Hyoudou
Voiced by: Sachiko Kojima (Japanese), Jessica Cavanagh (English)

Issei's mother and a full-time housewife. She is an excellent cook and sometimes goes out to a part-time job. She has unofficially adopted Asia as a second child and supports Issei's relationship with Rias. Issei's mother shares the title "Four Heavenly Kings" of the Kitchen along with Asia, Rias, and Akeno for their skill in cooking.

Morisawa
Voiced by: Tsuyoshi Aoki (Japanese), Ricco Fajardo (English)

Morisawa (森沢) is a regular client of Koneko and later Issei. He is a lolicon who likes to dress Koneko in various cosplay outfits. Like Issei, he is a huge fan of Dragon Ball (Drag So-Ball in the Anime).

Mil-tan
Voiced by: Kenta Miyake (Japanese), Chris Rager (English)

Mil-tan (ミルたん Miru-tan) is another one of Issei's regular clients, a male bodybuilder who wishes to become a Magical Girl. He ends his sentences with "Nyo" (にょ).

Mil-tan is shown to be stronger than an average human, being capable of withstanding Serafall Leviathan's Demonic Power that puts other humans to sleep. He was also able to battle the Witches from Khaos Brigade using his bare hands. He is also able to avoid letting Vali sense his presence.

Past Possessors of the Boosted Gear
The past possessors of the Boosted Gear whose consciousness are all stored within the Boosted Gear. Only two of the past possessors are named.

Belzard
Belzard (ベルザード Beruzādo) was a man known as the strongest possessor, defeating two White Dragon Emperors in his lifetime. He appears in Volume 9, singing the Oppai Dragon song lyrics before disappearing.

Elsha
Elsha (エルシャ Erusha) was a woman known as the strongest female possessor. She appears in Volume 9 alongside Belzard inside the Boosted Gear, providing Issei the "box" to tap into the full power of the Red Dragon Emperor. Her consciousness disappears soon after.

Other Possessors
Among the past possessors, there is a young man around the same age as Issei who was killed by another Longinus user after succumbing to the effects of Juggernaut Drive.

As of Volume 12, all the consciousness of the past possessors have disappeared from within the Boosted Gear after they sacrificed themselves to save Issei's soul which was on the verge of breaking down after receiving Samael's curse.

Momo Momozono
Voiced by: Risa Tsubaki (TV Momo) & Arisa Noto (Alarm Clock Momo) (Japanese), Elisa Castillo (English)

An anime-exclusive character, she is an adult video actress who portrays the tokusatsu heroine Kaben Rider Pinky (花弁ライダーピンキー Kaben Raidā Pinkī?, lit. "Pedal Rider Pinky", based on the Kamen Rider Series). Issei, Matsuda, and Motohama are all huge fans of her. She appears in the first episode of the anime where the Perverted Trio are watching Kaben Rider Pinky, and in the last episode as one of the various characters featured on Issei's alarm clock (albeit voiced by a different actress).

Susan
Voiced by: Ayako Kawasumi (Japanese), Monica Rial (English)

One of Issei's clients who appeared in the side story "The Work of a Devil", an American college student donned in samurai armor who is studying abroad.

Horii
Voiced by: Shinobu Matsumoto (Japanese), Chris Smith (English)

Susan's lover, a man donned in knight armor. Appeared at the end of the side story "The Work of a Devil".

Shuri Himejima
Shuri Himejima (姫島 朱璃, Himejima Shuri) was Akeno's mother and Baraqiel's wife. A priestess (miko) coming from a well-known shrine, Shuri saved Baraqiel's life when he was injured, and later fell in love with him. However, her relationship did not go well with her family, as they believed that she had been brainwashed by the Fallen Angel. To that end, her family sent well-known practitioners to dispatch the Fallen Angel and bring her back. They were defeated by Baraqiel, but some of them held a grudge against Baraqiel and told the faction who were against the Fallen Angels at the time about his location. Shuri was killed defending Akeno when several of Baraqiel's enemies attacked her home while the latter was away, resulting in Akeno's hatred towards her father for not protecting her mother. She returns as an apparition in Volume 7, encouraging her daughter to reconcile with Baraqiel as she knows that he still greatly cares for and loves them, before disappearing. It is revealed in one of the side stories that Shuri was a sadist like her daughter, and engaged in SM acts with her husband every night.