Lysithea is the eldest daughter and heir to House Ordelia. When she was two years old, her family suffered retribution from the Adrestian Empire for their role in House Hrym's revolt. She is a magical prodigy whose talents developed at an early age. In retaliation for House Ordelia answering House Hrym's call for aid, the Empire gained temporary control over the family while the Alliance turned a blind eye to avoid confrontation. The Empire killed key members of House Ordelia and replaced them with Imperial officials. Some of those officials were mages of Those Who Slither in the Dark, who then imprisoned the Ordelia children and began conducting Crest experiments on them. Lysithea's parents were powerless to stop them and could only watch in horror as their children perished one by one. Lysithea alone survived the experiments and gained two Crests: a Minor Crest of Charon and a Major Crest of Gloucester. The mages were pleased at their success, but because the procedure of implanting two Crests had dramatically shortened Lysithea's lifespan, they lost interest and departed. Due to her truncated life and the suffering her family had endured, Lysithea resolved to bring its affairs to an end. After completing her education and ensuring that her parents could live comfortably and in peace, she planned to eschew having children and dissolve House Ordelia. Lysithea enrolled in Garreg Mach Monastery Officers Academy in Imperial Year 1180, and joins the Golden Deer. She was the youngest student admitted. After the end of the Academy phase, she returns to Ordelia to assist her parents with governmental affairs. Though hailed as a prodigy, Lysithea is in truth an exceptionally hard-working student who desires to learn every day to improve herself to the maximum of her abilities. She states her skills do not come from natural talent, but merely determination and intense application and dislikes when people refer to her aptitude as merely a natural talent. She seeks to develop her skills as a form of independence so she no longer has to burden her parents, whom she loves dearly. As a result, Lysithea is constantly throwing herself into opportunities to learn as she seeks to make meaningful use of her every waking moment. She is efficient with her time and is annoyed when others waste it, developing impatience with those who provide even a minor inconvenience or hesitation. Her ultimate efforts have resulted in her being the youngest student in the Officer's Academy. As a result, she has a bit of a chip on her shoulder due to her age and dislikes when people treat her like a child, or at the very least she perceives they are doing so. She can be incredibly sharp-tongued when others annoy her or seem to be looking down on her. Though she attempts to act like an adult, Lysithea is terrified of ghosts and can be easily riled up when the subject is brought up. She is extremely fond of sweets, primarily cake, referring to it as "divine essence of the heavens". She treats it as if it was currency, as shown in a conversation with Felix where she gives him some to buy his silence. Try as she might, Lysithea tries to keep this fondness under wraps, but she often surrenders to her fondness and can be coaxed if it's used as an incentive. Lysithea's impatience is mainly attributed to the horrifying experiments she endured from Those Who Slither in the Dark who implanted a second Crest in her. While she was one of the rare survivors of the procedure, it left her with an extremely shortened lifespan, her hair losing all pigment and was given only a few years to live by Imperial Year 1180. Her desire for independence and separation from her parents is in reality to spare them from having to witness her horrifying fate. Compared to Edelgard, Lysithea is more open about her tragic childhood, revealing it to others in a majority of her supports. Due to this, she is also able to identify Edelgard as a victim of the same mages, despite Edelgard not telling her about her childhood. Lysithea has accepted her horrific fate, believing that she would have no place in the world. In the supports which lead to an ending that restores her lifespan, she realizes that her future is not set in stone, and resolves to fight on no matter what. Her dual crests are a closely guarded secret and few, if any, are aware of it. She displays disdain for Crests as a whole and would rather have been born without her natural Crest. She also resents her peerage and willingly gives it up in most endings. In some endings, she is able to have her second crest removed, restoring her lifespan and living a happy ending. In others, she lives out a short, but happy and peaceful life. A diligent Golden Deer student possessing great talent with magic. She loves sweets, but hates ghosts and being treated like a child. Lysithea is depicted with distinctive white hair, usually styled in a short bob with a few strands framing her face, and bright pink eyes; her appearance is directly tied to the experimental Crest implantation she underwent, which significantly shortened her lifespan and gave her unique hair color.

hardworking, sharp tongued, Phasmophobic, a little childish