Serafall Leviathan

Serafall Leviathan, formerly known as Serafall Sitri, is the current Satan with the title of "Leviathan" and Sona Sitri's older sister. She is the Satan in charge of foreign affairs.

Appearance
Serafall is a beautiful girl with long, black hair tied in twin ponytails and blue eyes (In anime, her eyes are violet). She also has a child-like body (albeit with large breasts).

She usually dresses in magical girl's clothing (from Magical Girl Milky Spiral Seven, the same outfit Mil-tan wears), magic wand and all, prompting Issei to coin her the nickname "Satan Girl" (魔王少女 Maō Shōjo).

Personality
Unlike her serious younger sister, Serafall is cheerful and possesses a childlike personality, which is evidenced when she addresses her sister as "Sona-chan" or "So-tan" and Sirzechs as "Sirzechs-chan". Adding to her childlike personality is the fact that most of her lines end with a star. She also has a deep sister complex, and has a tendency to get her sister into embarrassing situations.

History
Serafall is the older sister of Sona Sitri and the oldest sibling of the Sitri Family. During the war between the Old Satan Faction and Anti Satan Faction, she was part of the Anti Satan Faction that opposed the Old Satan Faction which ended in their victory and she was eventually promoted to the Satan Leviathan, losing her right as the heir of the Sitri Clan in the process.

Birth of the Breast Dragon Emperor
Serafall first appears in Volume 4 during the class observation day at Kuoh Academy to see her sister while getting attention from many photographers. Upon seeing her sister, she asked her why didn't she tell her about the class observation, claiming that she nearly attacked the Heavens out of shock. She and Sirzechs later attend the meeting between the leaders of the Three Factions, which was interrupted by an attack from the Khaos Brigade.

In Volume 5, she and the other Satans gather during the opening ceremony for the Young Devils Gathering and was unhappy at the fact that the elders of the noble families made fun of her sister when she announced her goal. She, along with the VIP from other faction are later shown to be viewing the Rating Game between Rias and Sona, feeling happy at the fact that her sister's servant, Genshirou Saji, is complimented.

The Heroic Oppai Dragon
In Volume 8, she participated in Issei and Rias' ceremony at the Ruins of Connection where she acted as Satan Pink and tested them on dancing.

In Volume 9, Serafall came to Kyoto for a peace talk with the Youkai, but this did not occur due to the Hero Faction kidnapping their leader. The peace talk, however, was successful after Issei, his friends, and Sun Wukong managed to rescue Yasaka.

In Volume 12, Serafall goes to the front lines herself, being unable to bear with the the crisis faced by the Underworld, defeating one of the Bandersnatch with ease.

Powers & Abiities
Ice-based Magic: Serafall specializes in using ice-based magic, as opposed to her family's trademark water-based magic.
 * Celsius Cross Trigger (零と雫の霧雪(セルシウス・クロス・トリガー) Serushiusu Kurosu Torigā): This is Serfall's signature technique which convert the land itself into a world of ice, as shown when she froze up an entire region of the Underworld along with the monsters created by Annihilation Maker with ease.

Immense Demonic Power: As the current Leviathan, Serafall is a powerful Devil. Her sister Sona once stated that Serafall could destroy the nation of Japan several times over if she so much as "glitters". Serafall is also regarded as the strongest female devil in the Underworld.

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

Trivia

 * Serafall has her own TV show in the Underworld called "Miracle☆Levia-tan" (ミラクル☆レヴィアたん Mirakuru☆Revia-tan), which has a rivalry with Oppai Dragon.
 * Serafall sees Gabriel as her biggest rival.
 * The only known member of Serafall's peerage is the "Magical Beast King of the Earth", Behemoth.
 * Serafall has a tendency of adding the suffix "chan"(ちゃん) on everyone she knows.
 * Serafall has stated that she still has spare Evil Pieces and has shown interest in making Mil-tan her servant.
 * Serafall choreographed the music video of "The Song of Oppai Dragon".
 * Serafall's name is derived from the names of four female characters from the Gundam TV series; Sayla Mass, Lalah Sune, Four Murasame, Roux Louka.