Sirene

Sirene is a major villain from Devilman, in the anime she was just a monster-of-the-week, but in the manga she is the first major threat towards Akira Fudo (AKA Devilman). Sirene appeared in several different related media by Dynamic Productions including Mazinger Z vs. Devilman, often as a villain.

Production History
Sirene, as described in the manga is a demon of great beauty that is not found in many other demons with origins that vary on the media. During the time the demon tribes ruled the Earth she encountered the exceptionally powerful demon Amon (the Demon that would eventually fuse with Akira which would cause the human to become Devilman), and became his companion. Sirene took a liking to Amon, but it is not explicitly stated on what Amon thought of her. When Amon became fused with a human, Sirene was enraged by the fact that Amon had been taken over by what she called a lower lifeform and sent several assassins after him before going in for the attack herself, being mortally wounded in their fight and is fused together with her companion Kaim until dying from her own wounds.

In the Devilman anime, Sirene did not have any known relationship with Devilman (Amon's anime counterpart) aside from being a fellow soldier. She kidnapped Miki and challenged Devilman to a fight, dropping Miki into a volcano. While they were equal, Sirene was defeated when Devilman used his Devil Beam attack to evaporate her.

Appearance
Depending on the media, Sirene has different appearance. In the manga, Sirene has fair white skin and white feathers. Her forelimbs are like that of birds. She has wings on her head that allow her to fly and tail feathers. Her human-like face is beautiful until provoked. Her breasts are also exposed while her groin area is covered with small feathers.

In the anime, Sirene has blue skin and dark blue feathers. She also wears a brown garment over her body.

Personality
Sirene is a highly prideful demon, refusing to fuse together with other demons as it would soil her appearance. She like many other demons see humans as lower lifeforms unfit to live on Earth. She had a one-sided love for the strong demon Amon and was disgusted when she discovered that a human took over his form and powers and started many attempts to kill the human, Akira Fudo. She was rather close with her companion Kaim, refusing to kill him out of their bond but on his suggestion she did so to fuse with him.

Abilities
Like many other demons, Sirene has the ability to fuse with living things including other demons to gain stronger forms. She does not use this much as it would ruin her appearance. Sirene is able to fly with her light weight and the wings on her head. She is also able to throw her forearms as razor sharp boomerangs.

Mazinger Z vs. Devilman
Sirene for some reason was sealed underground away from the other demons until she was freed from the fighting of the Mazinger Z, Aphrodite A, and Mechanical Beasts. After escaping, she strikes an alliance with Dr. Hell so that both sides would destroy their enemies. Sirene was sent to deal with the Jet Scrander that would allow the Mazinger to fly along with an amorphous demon. While successful in damaging the craft, Devilman comes to fight them and Sirene takes Shiro Kabuto and Sayaka Yumi hostage to escape before dropping them with Devilman coming to the rescue. Sirene along with the other demons capture Devilman and torture him until meeting her fate with the Mazinger now equipped with the Jet Scrander.

References in Mazinger
As said in Go Nagai's autobiography manga Gekiman!, Sirene's ability to throw her forearms served as the inspiration for the Rocket Punch. Mazinger Angels features one of the main robots having an alternate form based on Sirene, with the pilot wearing a costume based on her during one chapter.