Grayfia Lucifuge

Grayfia Lucifuge is the mother of Millicas Gremory, the older sister of Euclid Lucifuge, the sister-in-law of Rias Gremory, and the wife and Queen of Sirzechs Lucifer. She is known as the Strongest Queen and the Silver-Haired Queen of Annihilation, and is the only member of Sirzechs' peerage who stayed behind after the events of 666.

Appearance
Grayfia is a beautiful woman appearing to be in her early twenties, with silver hair and red eyes (Silver in the anime). Her hair, which flows all the way down to her back, features a long braid on each side with small blue bows at the ends, while the rest is let down, ending in twin braids.

In most of her appearances, she is seen wearing a blue and white French maid outfit with long sleeves and a white maid headband over her head, with red lipstick as a cosmetic accessory.

Personality
Grayfia has a very strict personality, and is often exasperated by her husband. She also does not like admitting her relationship to Sirzechs while she is "on the job", to the point of pinching Sirzechs' face if he mentions it, and denying it. Grayfia also has an issue where she becomes a "troublemaker" as stated by Azazel, who was told by Sirzechs, when she becomes drunk. Despite her serious personality, Grayfia also showed that she is a kind and wise lady who deeply loves her family and enjoys doing her "job" as a maid of the Gremory Clan.

History
Grayfia comes from the House of Lucifuge, a noble family of Pure-Blooded Devils from the Extra Demons whose family served under the original Lucifer. Grayfia was originally from the Old Satan Faction that opposed the Anti-Satan Faction, where she stood in the front lines as one of the most powerful Devils. It was during that time that she met Sirzechs and fell in love with him. During the Devil Civil War she would meet him in secret. The two of them married each other after the end of the conflict between the Old Satan Faction and the Anti Satan Faction, eventually giving birth to a son. Their romance became a well-known romantic story among the young Devils and was even made into a movie.

The Red Dragon Emperor's Awakening
Grayfia made her first appearance in Volume 2, stopping Rias from having sex with Issei to break off her engagement. She later arranges a Rating Game between Rias and Riser Phenex, the third son of the Phenex Family and Rias' fiancé at that time, with the consent of Rias' family. Later on after the Rating Game Issei wakes up when Grayfia informs him that his team had lost the match and that Rias is currently in the Underworld preparing for engagement ceremony with Riser, however she gives a way to transport there from Sirzechs, thus giving him another chance to win Rias back.

Birth of the Breast Dragon Emperor
In Volume 4, Grayfia accompanies Sirzechs to the human world, when Sirzechs goes to the Hyoudou Residence to visit Issei's parents as well as for Rias' class observation day.

In Volume 5, she and the other maids and butlers of the Gremory Clan welcomed Rias and her peerage who returned to the Gremory Region, preparing a carriage for them. She later serves as the arbiter during the Rating Game between Rias and Sona.

In Volume 6, she is seen to be taking care of Issei along with her son, telling her son not to call her mother when she is doing her job.

The Heroic Oppai Dragon
In Volume 8, she took a day off as the Maid of the Gremory Clan and visited the Hyoudou Residence as Sirzechs' wife and Rias' sister-in-law. She went to inspect the house and to see how Rias is doing, as she is going to be the future heir of the Gremory Clan. She later acted as Satan Yellow during the trial for Issei and Rias at the Ruins of Connection before properly acknowledging them as the Master and Mistress of the Gremory Clan.

In Volume 11, she accompanied Sirzechs to the Hyoudou Residence when Sirzechs was getting the confirmation from Issei, Yuuto, and Akeno for their Middle-Class Promotion Test.

In Volume 12, she and the members of Sirzechs' peerage goes to the front line to fight the Jabberwocky but could not make much progress due to its high regeneration ability. They were later successful in defeating the Jabberwocky after Issei (in Super Gigantic Balance Breaker form) assisted in the battle and uses the Longinus Smasher to destroy the Jabberwocky without a trace.

The Legend of Oppai Dragon and his Lively Companions
In Volume 13, Grayfia arrived at the Hyoudou Residence just before Issei and Sirzechs, in his Satan Red costume, are about to fight and stopped them. She also reprimanded the Lucifer group (without Enku and Bahamoot) for not telling her where they're going and going to the Hyoudou Residence without prior confirmation.

In Volume 15, it was stated by Issei that Grayfia was shocked when she learned that her brother, Euclid, is alive. The higher-ups of the Underworld started to panic and became suspicious of Grayfia, thinking that she lied about his death, and began interrogating her.

In Volume 18, it was mentioned that Grayfia was chosen to be the one to interogate Euclid due to his request for his sister. When the Lucifuge siblings were reunited for the first time after centuries of separation, Grayfia harshly reprimanded Euclid for choosing to support Rizevim's atrocious ambitions and engaging in terrorism solely because of their Clan's law of complete obedience to Lucifer.

In the Extra Life of DX.1, Grayfia became the arbiter for the Rating Game rematch between Rias and Riser.

In Volume 21, Grayfia appears along with the members of her husband's peerage intending to follow Sirzechs into the Isolation Barrier Field. To her dismay, Sirzechs uses a hypnotism method taught by Azazel on her as Grayfia fades into unconsciousness while lamenting the fact that Sirzechs is leaving her behind.

In Volume 22, Grayfia returned to her usual duties as a maid, hiding her emotions about Sirzechs which Rias is worried about. Grayfia took part in Rias's graduation, however she was sitting away from her family with Millicas staying next to her.

Red Dragon Emperor of the Blazing Truth × White Dragon Emperor of the Morning Star: The True Dragon(s) of the Kuoh Academy
She joins Issei's team as his Queen under the alias of "Bina Lessthan" for the Rating Game World Tournament with Issei and Ravel being the only ones who know her true identity. After ten days, Grayfia receives better ratings than the rest of the team. During the match against Baraqiel, Grayfia assisted Rossweisse and takes on Armaros, while also releasing extraordinary amounts of demonic power.

Powers & Abilities
Immense Demonic Power: Even for an Ultimate-Class Devil, Grayfia is very powerful, being noted by Rias and Euclid as one of the strongest Devils of the Old Satan Faction and referred to as the Strongest Queen. In fact her power is on par with the Four Great Satans, having extreme amount of demonic powers. Even Sirzechs a Super Devil himself is terrified of his wife when she is angry. Grayfia can also create a red magic circle in the form of a dragon.

Flight: Being a Devil, Grayfia can fly using her wings.

Trivia

 * Grayfia's height is 174 cm. (5 feet 8 inches) according to the visual book with her data, making her the second-tallest female character in the series (after Kalawarner).
 * Grayfia's last name, Lucifuge, is a reference to Lucifuge Rofocale, a demon in charge of Hell's government and Lucifer's subordinate. Her role as Sirzechs' wife and Queen, as well as her family's lineage of serving the original Lucifer, justify this reference.
 * The original Japanese spellings of Lucifuge, ルキフグス Rushifugusu, can be translitered as Lucifugus, the original spellings in Latin for "Lucifuge" (both meaning "to flee the light"), and its counterpart Rofocalus for "Rofocale".
 * Grayfia bears a near-exact resemblance to Sakuya Izayoi of the Touhou Project series.
 * Grayfia once challenged Serafall Sitri for the title of Leviathan.
 * Grayfia has two different roles in the House of Gremory, as a maid and as Rias' sister-in-law. Normally, she acts as a devoted maid and on special occasions, such as her day off, she acts as Rias' sister-in-law, during which she lectures her.
 * The "Let's Go Onsen" short story reveals that she has low alcohol tolerance.
 * Grayfia's name is derived from the names of two Pokemon: Glaceon and Leafeon.
 * Apart from Sirzechs, Issei is the only other man to have seen Grayfia naked.
 * The meaning of Grayfia's first name alias "Bina" in Italian means "double", referring to the fact she was using a double personality to hide her own.