Mary Beelzebub

Mary Beelzebub( メアリー・ベルゼブブ; Mearī beruzebubu), previously known as Mary Purson(メアリー・プソン; Mearī Puson) is one of the current Seven Great Demon lords, the wife of Calico Belphegor and Irene Dantalion's mother. She's also Alice Gremory's best friend and Cohen Lucifer's rival in the Highschool DxD: Яe-birth.

She's one of few surviving devils that fought during the Great Apocalypse, making her a living legend and a hero among her peers. Mary is the Chief Advisor for the Technology Department, Succeeding Ajuka Beelzebub, being also a doctor at the Beelzebub hospital

Appearance
Mary is described as a a tall, pretty and slender woman with bright green wavy hair with several ribbons wrapped in them, fair skin and equally emerald eyes, wearing a medical coat over an tight leather black jumpsuit and carrying several needles with her. It is noted that she wears a monocle under her right eye after Cohen almost blinded it during a fight.

Personality
mary is usually a very stoic and calm woman, maintaining a professional façade even during normal conversations with her friends and arcquantances. She hates to be disturbed during her job, and even while maintaining her usual demeanor, Ichijou notes she oozes a rather dangerous and malicious aura even heavier than any other devil's he ever encountered. However, she'll honestly apologize if her small displays of intimidation affect those unrelated to her wrath, showing such affable side also to her patients who she swears to cure.

However, she carries a certain amount of animosoty towards her Childhood friend Cohen Alastor, and is usually stoically enraged when remembered she lost the position of Lucifer to him. She also hates to be compared to her predecessor Ajuka Beelzebub, and wants to surpass him in order to prove herself the smartest of the two. She won't forgive those who try toi diminish his name or title though, showing some degree of respect for him.

Mary seems to take a liking of Cohen's daughter and her peerage, saying a kind of those is only born every century.

History
Mary is the youngest daughter of the Purson clan, the childhood friend of Alice Gremory and Cohen Lucifer, who she used to bully due to his Alastor heritage, somewhere before the Great Apocalypse. She was taken under the wing of the Demon Lord of Beelzebub Ajuka due to her massive intelect, in which she then developed the wish to surpass him someday. She fought alongside Calico and Cohen during the great Apocalypse, and during the reconstruction of the Underworld, fought against the Latter for the position of Lucifer, losing and almost being blinded on her right eye, instead inheriting the position of Beelzebub and Chief Advisor for the Technology Department.

A few years prior the start of the fanfic, she married Calico as an experiment and had a daughter with him, Irene, who inherited both their signature abilities.

Powers & Abilities
Immense Demonic Power - Inheriting the title of the demon Lord Beelzebub and being considered a Super Satan, Mary is one of the strongest devils in the Underworld, only under her Rival Cohen and Grandmaster Millicas in terms of power, being a mile stronger than the other demon Lords besides them. In fact, if by any reasons she was to be put in a battle position, her presence would be considered an affront against all of the other factions and a declaration of war altogether.

Venom - Being a member of the Purson clan, Mary's blood is actually poison, which lethality can vary from anesthesiac to certain death. She uses her poison instead to help her patients at the Beelzebub hospital, rarely using as a form of weapon, altought she uses syringes in order to reach them. While mastering such powers, the lethality of the poison is controlled by and deep proportional to her emotions, and as such, if she's either enraged or deep in thoughts, her skin becomes darker since her poisonous blood becomes deadlier. Specialized Demonic Power: With the wish to surpass Ajuka someday, Mary developed her own form of specialized demonic magic that uses letters instead of numbers. For being still under development, this form specializes in modification instead of Creation, unlike Ajuka's, and therefore weaker. Master Modifier- While as yet to develop something herself, the other Demon Lords admit that Mary is a master in adapting and motifying anything she touches for the best, as she has immense knowledge about the Evil Pieces, Sacred Gears and others alike.
 * Poison Rune(ポイズン・ルーン; Poizun rūn) - A form of poison Mary developed herself for her magical attacks. Mary can create runes with several effects and embed them with poison, creating things such as poisonous fireballs, poisonous ice or even poisonous lightning, which poison anyone attacked by them.
 * Goetia Fetus - Also known as Birth of the devil, is another special ability developed by Mary. If by any chance her poisonous blood is unable to create a cure for any kind of venom, for example Albion's [REDUCE] venom or Cohen's poison, Mary can create from her body a fetus-like child that carries her brain and all the information it has, which them matures and becomes a new Mary. A technique created for escaping strategies, it also enables the new Mary to developed a stronger body against stronger poisons at the cost of some years of her lifespan.
 * Ars Lexicon - One of Mary's specialized moves in which she can change the properties of any form of magic or phenomenom that happens on her Vicinity.

Master Healer - Being a doctor chief at the Beelzebub Hospital and a Purson, Mary has a vast knowledge about medicines and antidotes for any form of patients, as she can cure or help anyone as long as she has a quick look into their data, and even produce some antibiotics herself with her blood.

Master Marksman - Mary seems to be also very good with projectiles and have a pretty accurate aim, as she can hit veins with extremely precision against fleeing patients or foes with syringes and nothing else.

Inventions
Despite not being a proper inventor, Mary has the power to modify and create something completely different out of already existent concepts, which earns her the title as Ajuka's successor:
 * Fairy Pieces - Also known as Piece of Recolocation, is a special type of Evil Piece any Rook, Bishop or Knight can use once per game in Rating Games. By using it, one of the said pieces can adquire a new special trait from any other piece in order to compensate one of their weaknesses.

Trivia

 * The images and appearance used are from the Salve Trader from the

ISEKAI MAOU TO SHOUKAN SHOUJO DOREI MAJ series.UTSU