Marianne vi Britannia

Marianne vi Britannia (マリアンヌ ヴィ ブリタニア, Mariannu vui Buritania), 38 years old (30 at the time of her "death"), was the late Empress of the Holy Britannian Empire. She was the fifth wive of Charles zi Britannia and was the mother of Lelouch vi Britannia and Nunnally vi Britannia. She was formerly a member of the Knights of the Round and held the titles of Knight of Six, and later Knight of Two.

Personality
Because of her death, little is known about Marianne as a person; early Code Geass side materials portray Marianne as a sweet, kindhearted woman with a rebellious spirit and a deep protective instinct towards her children. Lelouch gives two examples of this: in one she rode a horse into the palace's great hall and in the other she picked a fight with several of the Emperor's other wives all at once. In a flashback from one of the novels, she uses the Ganymede to intimidate a fellow consort who had been harassing Lelouch and Nunnally — all the while maintaining her friendly disposition. Later, side materials reveal her true nature as a selfish, heartless former member of Knights of the Round who helped to overthrow the previous Emperor of Britannia and install Charles as the 98th Emperor. She only superficially loves her children and will not hesitate to kill them if they get in her way.

It is also revealed in the official novel that she is even crazier than Charles in Geass and had made many test experience of Geass on many people, including Lelouch and Nunnaly, who she viewed as the most successful exprerience subjects despite the fact that they were her own child. She is even willing to go so far as considering to make Nunnaly have Lelouch's child to create a perfect container of the Code.

Marianne's conversations with C.C., one-sided in the anime but scripted out by the staff (and actually revealed in the Nintendo DS game), show that she has a playful side, often teasing C.C. when the immortal girl tries to deny any sort of attachment to Lelouch.

Character Outline
Marianne vi Britannia is the late 98th Empress of the Holy Britannian Empire and the mother of Lelouch and Nunnally. Her commoner status by birth caused her to earn the jealousy of other imperial wives and nobles, which Lelouch suspected had resulted in her murder. Lelouch's investigation revealed, however, that several members of the Imperial House not related to her by blood respected and admired Empress Marianne, such as Clovis, Euphemia, especially Cornelia, who idolized her and put a lot of fruitless effort into investigating the assassination.

It is hinted that her supporters were the Ashford Foundation, which explains why their social statuses were ruined after her death and why they consented to protect Lelouch and Nunnally. She had also piloted one of the earliest Knightmare Frames, the Ganymede, which was developed by the Ashford family and is well known for her superior Knightmare Frame piloting skills, hence the nickname, "Marianne the Flash". She also became a member of the Knights of the Round thanks to these skills. Several times throughout the series, Marianne's consciousness has been shown to be communicating with C.C. as a side effect of her Geass.

First Season
At the end of season one, Lelouch, by questioning Cornelia using his geass, discovers that Marianne had ordered Cornelia to shut down the security on the day of her attack, implying that she knew about the attack beforehand. It is eventually revealed that the security was lowered by Marianne under the request of V.V. and he was the real culprit, who killed Marianne out of jealousy.

Second Season
Marianne's spirit is revealed to be within Anya Alstreim's body. She recovers C.C.'s memories and by using the Mordred heads to Kamine Island with C.C. to help Lelouch. While making their way to Lelouch and Charles, they encounter Bismarck Waldstein who is currently engaged in battle with the geassed reinforcements of Shinkine Island. Marianne did not want to waste time and so tricked Bismarck questioning his loyalty. Knowing that he wouldn't question hers, believed her, allowing her to lie saying that she will intercept the rebel forces from the ground. C.C. acknowledges Marianne's ability stating that, her nickname "Marianne the Flash" suits her and being the mother of her son Lelouch. She is revealed to have had a contract with C.C., though she never fulfilled her end of the bargain by becoming immortal through acquiring the Code. She attempts to aid Charles in triggering Ragnarök, but is killed when Lelouch uses his Geass to turn the gods on them both.

Geass
Marianne's Geass allows her to transfer her spirit (along with her geass) into another person. A side effect is that, when her consciousness surfaces, she can speak with C.C telepathically. She used it after being mortally injured by V.V.. If her body was kept intact, there was a possibility that she could have returned to it.