Plenty of demons only make a single apperance, mostly because very few demons survive after meeting the Devilman for the first time.
Akemi was a high schooler who was getting drugs from foreign crimminals. With the drugs she'd transform into a Devilman and rob jewelery stores for them. When she demanded a cut of the jewels for serself the crimminals attempted to punish her by raping her. This, however, just caused her to transform even without the drugs and kill them. She continued to rob stores until she ran into the Devilman Lady. Akemi continued to grow more powerful as she slipped farther into a devilbeast while Jun held back in the hope of saving her. Akemi was killed when Devilman Liger made a sudden appearance and ripped her in half.
Akemi made a short cameo in one of the Neo Devilman stories. In it she is suddenly warped into the forest of suicide in Hell. She meets Akira and follows him before finding her way back into the living world.
Anne was a nun who was found to be harboring fugatives. She was put to death for doing so, and her sorrow was imparted into her locket, a locket that eventually ended up in the hands of Miki. Akira sensed something in the locket, and when he took it to Ryo to look at both of them were transported to Anne. She attempted to kill them, as she believed that only death ended suffering, but Akira was able to convince her to have faith in life again. Akira and Ryo were transported back to Japan and Anne began using her powers to help the sick and wounded.
In the Devilman Lady anime Aoi was a classmate of Jun's who wanted a more personal relationship with her. Jun turned her down, creating a lasting resentment which eventually awakened Aoi's Beast gene. She killed many women just for fun before finally meeting the Devilman Lady, and was killed.
In the manga only one of Aoi's multiple personalities became a devilbeast. Her remaining personality was pushed out of the beast and survived. She later awakened Devilman powers and joined the Human Alliance, now calling herself Devilman Noir. When she met Jun again her passion was renewed and her lust fueled a new change in her body, allowing her to grow a penis. She attacked Jun but was defeated yet again, and died from a great fall. When Mao Dante opened a portal to hell her body was possessed by the spirit of Sirene.
Bela is a harpy living in the Tibetan mountains. She reanimates a recently deceased corpse and then controls it to kill its former wife. This process continues, the living being slain and their corpses reanimating, until the entire village is under her control. She then sics the villagers on Akira and the Makimuras, but Akira gets away from the zombies and is able to kill Bela without much of a fight.
Ebain is an armless centaur who lives inside mirrors. She can appear in any mirror and control the arms of humans near her. After Devilman stops her she plots to trap Devilman in the world of mirrors, where she will be at an advantage. Although she is powerful, and has a thousand arms that she collected from her victims at her disposal, she is still defeated when she is stabbed in the eye by her own horn after it is broken by Devilman's Devil Arrow. The thousand arms then turn on her and strangle her to death.
Faim is a fire sprite that delights in burning anything combustable. She is entrusted by Xenon to deliver the beast Gondoroma to General Zannin, but because of Zannin's bad attitude and how he treats Gondoroma she decides to free the beast instead. She reveals herself as a big fan of Devilman and helps him during his fight with Zannin. She is snuffed out after she falls into a lake.
Ganda & GandaiEdit
The sibling trio Ganda, Gandai, and Gande are tasked with defeating Devilman. Ganda and Gandai attack Devilman first to uncover his powers, then all three combine together and use what they've learned to outwit him. Devilman used his Devil Beam to blind them, which they did not see coming, and then kills all three.
Harpy is an awakened Beast Gene possessor who has been killing people at the bequest of Satoru for at least several years. She murders Kazumi's family to send a message to Jun. She is caught off guard when the Devilman Lady grows wings, and falls to her death after her own wings are ripped off by the Lady. She later reappears, along with several other Beasts, as phantoms conjured up by Izumi Kogure to torment Jun.
Heavenly Gate GangEdit
After Jun goes on the lam Kazumi falls in with a group of teenage Devilmen. The four of them, Chika, Misaki, Mayu, and Kyoko, retain inhuman features even when not transformed, and therefore need to hide to keep from being reported to the anti-Beast police. The group manages to survive by scrounging for awhile, but eventually the police crack down. Chiaki sacrifices herself so that the others can escape, but they wind up incarcerated anyways. Despite several escape attempts they remain incarcerated until Asuka's defeat at the end of Devilman Lady TV.
Hitomi was a model who applied for many of the same jobs as Jun. In secret she was actually stalking Jun, and believed herself to be in love with her. After she convinces Jun to meet her at home Hitomi drugs, strips, and restrains Jun in her bed. Whatever she was planning on doing to Jun, Hitomi decides to kill her after her Beast gene awakens. Their fight ends when the Devilman Lady snaps Hitomi's spine.
Iyamon and her brother Bou are tasked with killing Miki in order to break Devilman's spirit. Iyamon disguises herself as a classmate of Miki and, after hypnotizing the class, almost succeeds at sucking the life force out of the girl. After she is inturrupted the second time Devilman comes after her, then ties her up and whips her to find out how to restore Miki's health. Even after both Iyamon and her brother are killed by Devilman she still says that there is no way to restore Miki and that she will die in one week. That was a lie, however, and Miki recovers on her own.
Izumi is assigned to be Lan Asuka's secretary by the Japanese government after the Beast issue becomes widly known, possibly to keep tabs on Asuka. In secret Izumi is also one of Satoru's four underlings, and uses the knowledge she has access to for the purpose of furthering Satoru's plans of ending human civilization. When transformed into Beast form she has the ability to create puppet monsters based on a person's fears and past enemies. She joins with Satoru and the other three underlings to create a massive Giga Effect Beast in the hopes of killing Jun, and is presumibly slain when Jun kills the Beast.
Laffolil is a plant demon that can cause earthquakes and cave ins. She can appear as three women, but can also transform into a burrowing root, or a giant head with prehensive hair and root limbs. She attempts to put Devilman to sleep with enchanted pollen, but he overcomes the powder and kills her with a Devil Beam.
Mameimu is a mermaid and master of water. She is tasked with assisting General Zannin with defeating Devilman, but traps Zannin in an illusion so that she can have Devilman all to herself. She manages to trap Devilman and the Makimuras in giant underwater clams and then goes on to flood the nearby city. After Devilman frees himself and his adopted family he destroys her staff, limiting her powers. Mameimu still has the ability to transform into a living puddle, but while she can trap Devilman in her body she can not survive his Devil Beam.
Mari appears in Volume 13 of the Devilman Lady manga. She is the daughter of a salaryman who, after becoming a crocodile-like devilbeast, aquires a taste for meat. Unfortunately for her parents she later decides she prefers fresh meat. She is killed by Devilman Kids.
Maria is the right hand woman of Yuda Hiraoka, the leader of the Cult of Dante. Like Yuda she is also a Devilman and wants to see the world ruled by a new order of Devilman. Also like Yuda she is one of the three heads of Zenon, and merges with Mao Dante after he returns from Hell. Her Devilman form is a 20-meter tall feline centuar.
When Devilman and Devilman Lady travel through Hell they are momentarily attacked by the mythical Medusa. This is probably not the same Medusa from Mao Dante.
Later, after Mao Dante destroys Hell and frees its residents, Medusa is restored to her human beauty and flees along with everyone else.
Memu is a slug demon who enchanted men and made them fight over her. She took a job at a coffee house and disguised herself as Moyako. After she drove several boys to nearly kill one another Devilman was able to uncover her identity. He caught her off guard with a frog, which she was terrified by, and then impaled her with a tree trunk and finished her off with a Devil Beam.
Michiko is a classmate of Akira who fantisizes about one day marrying him. She is successfully possessed by a demon because of her emotional state at the time, and the demon, now in complete control, kills the rest of her family. The demon too feels an intense attraction towards Akira, which it perceves as a desire to eat the Devilman and gain his power. She gets a chance when she stumbles upon the human mob that murdered Miki, but she is killed in a single blow by Akira.
Plenty of demons appear in Devilman that are never named.
Mugaaru also known as Texsch is one of the demons that attacks Akira and Ryo prior to Ryo's Black Sabbath. She attempts to attack the two while they are in Ryo's car, but they manage to get away from her. She later reappears in a Neo Devilman short story where she attacks a detective investigating the events at the mansion. In Devilman TV Mugaaru hypnotizes Akira's teacher and principal and makes them believe that he killed Miki in order to ruin his good name. Akira eventually sees through Mugaaru's illusions, finds Mugaaru's real body, and destroys it. In the TV version Mugaaru has a male voice actor, but still has a recognizably female body.
In Devilman Lady a student in Jun's swimming class, Suzuki, has a Devilbeast form similar to Mugaaru. Without Jun even noticing it she became a Devilbeast and used her hypnosis powers to control men in the school. She was surprised when Jun became Devilman Lady, but her powers worked even on the Devilman, leading her to hatch a plan. Jun was given a hypnotic suggestion to transform into Devilman Lady infront of the entire school at a school assembly.The plan almost worked, too, until a bomb went off and the building was evacuated. Left alone with Jun Suzuki decided to just transform and kill her, but after a close fight Devilman Lady and the HA forces were able to kill Suzuki.
Nami was a pop singer. Unknown to her, her mother had become a bird Devilbeast and was flying around the city, killing people. Asuka and Jun tracked Nami's mother back to their apartment, but Nami demanded they leaver her mother alone. In her anger she turned into a bird-like Devilbeast herself and attacked Devilman Lady. Asuka was able to get the upper hand and kill Nami's mother, while Lady knocked out Nami and returned her to near-humanity. Persumibly she was forcibly enrolled in the Human Alliance afterwards.
Noriko was an officeworker having an affair with a man from her office when her Beast Gene activated. Her desire to have a child was so great that she absorbed her (kind of an asshole) lover, as well as several others, in order to impregnate herself. Her Beast Gene transformed her into a plant-like creature with toothy, crocodile-like jaws and dozens of tentacles. She was killed in a single blow by the Devilman Lady.
Demon Marshal ReikokuEdit
Reikoku is the third and final of the overseers to orchestrate demonkind's attack on humanity. She ordinarily dwells in the night sky, and personifies her demons in her jewerly and clothing. After the death of Arunon, Reikoku's sister (who was living inside her dress), Reikoku attacks Devilman in a rage. Devilman manages to slay her dragon mount, but her prehensive hair and seeming immortality thwart his attacks. Finally Devilman realises he must destroy the true image of Reikoku on her jewlery, and soon after finishes her off for good.
Zaldover is a powerful witch demon who tried to defeat Devilman. She could cast powerful magic and illusions inside her mansion, and was also able to transform into the disgraced demon Lita after eating her. Devilman overpowered her and burned both her and her house down.