vi Britannia Marianne
Despite her rank as a Knight of the Round, Marianne's commoner status by birth earned her the jealousy of other imperial wives and nobles, which Lelouch suspects resulted in her murder. However, several members of the Imperial House not related to her by blood are shown to have respected and admired her, including Clovis, Euphemia, Jeremiah (whose first posting was as one of her bodyguards), and in particular, Cornelia, who commanded Marianne's personal guard and put much fruitless effort into investigating the assassination. Under the influence of Lelouch's Geass, Cornelia notes that Marianne had ordered her personal guard to leave on the day of her attack, implying that she knew it was going to happen. Her assassination also resulted in the disgrace of the Ashford Foundation, another suspected motive. It is eventually revealed that the culprit was V.V., who killed Marianne in the middle of the night out of seeing her as a hindrance to their plan, as well as out of jealousy for the attention Charles paid to her. He then arranged a cover up with Nunnally as a witness.
However, Marianne made a pact with C.C. prior, giving her a Geass ability that allowed her to project her conciusness onto people's minds through eye contact. She activated the ability as she was dying, transferring her mind into the body of Anya Alstreim, who happened to be there at the same time. From there, Marianne contacted C.C. via a form of telepathy, though the viewer only hears C.C.'s side of the conversation. Marianne seems to enjoy teasing C.C., especially when the immortal girl tries to deny any sort of attachment to Lelouch. The full conversation is scripted out by the staff and revealed in the Nintendo DS game. But when Charles begins the final steps of his plan, Marianne takes control over Anya's body to take herself and C.C. to Kamine Island. Once there, Marianne discards her host to aid Charles in triggering Ragnarök as they planned, regaining her physical form within C's World. However, she dissolves when Lelouch destroys the connection and turns the world's collective unconsciousness on her and Charles.
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: she once rode a horse into the palace's great hall, and another time she picked a fight with several of the Emperor's other wives all at once. In a flashback from one of the novels, she used 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 ruthless former member of the Knights of the Round who helped overthrow the previous Emperor of Britannia and install Charles as the 98th Emperor.