Laeticia (レティシア, Retishia?) is a French girl who is chosen by the Holy Grail as a match for the materialization of Ruler Jeanne d'Arc in the Great Holy Grail War of Fate/Apocrypha. After accepting the role, her personality is temporarily suppressed for most of the war.
Laeticia is a normal girl in France living in a student dormitory.
Laeticia is "ideally close" to Jeanne in appearance in acting as a possessed vessel. Her facial features and style are partly similar, so her appearance was changed slightly by the possession. She also has a slightly larger bust size than Jeanne.
Laeticia is described as decent and honest, possessing a religious piety that surpasses many others. She accepted Ruler's request without question despite her normal life, being dragged into the Holy Grail War. While Ruler is in control of her body, she is able to witness Ruler's actions and communicate with her. It is much like "watching a movie inside a dream for her", the memories fading fast after Ruler departs from her. Despite not remembering, her prayers have gone from being vague to having taken on the direction of wishing that “those two may find happiness together.” She prays daily believing in small miracles such as that.
While Jeanne initially believes Laeticia to be harboring feelings for Sieg, Laeticia was simply a witness to their relationship. She was the "final stronghold" for Jeanne not realizing her own feelings of love for Sieg.
Laeticia becomes the vessel for the Ruler-class Servant, Jeanne d'Arc, a possession she wholly submits to out of faith. Laeticia remains mostly dormant as Jeanne carries out her duty as mediator for the Great Holy Grail War.
When the Hanging Gardens of Babylon start to collapse, Caules Forvedge Yggdmillennia and Rider of Black carry her to safety on Hippogriff. Afterwards, she thanks them and bids them farewell before returning home.
- ↑ 1.0 1.1 1.2 1.3
 Fate/Apocrypha material - Encyclopedia: Laeticia [Person's name], p.189 [T]
Laeticia [Person's name]
The French girl who Ruler chose as her possession vessel. She’s a decent and honest person who has no Magic Circuits, but her religious piety alone surpasses that of others. Though she has lived an extremely normal life, she loaned her body upon Jeanne d’Arc’s request. Her facial features and style is only partly similar to Ruler’s. Due the effects of the possession, her body was somewhat changed to match Ruler’s. After Ruler left her body, she returned to normal.
She served as the witness to Ruler and Sieg’s relationship, and she was, in a certain sense, the final stronghold for Jeanne, a sheep that allowed Jeanne not to notice her own feelings of love.
She is an ordinary person who got dragged into the Great Holy Grail War, but emotionally it was like watching a movie inside a dream for her, and after it ended her memories of it wore away in the blink of an eye. Even so, she doesn’t make vague prayers anymore, as she found a direction for her prayers in the form of wishing that “those two may find happiness together”, and she prays believing in such small miracles every day.
- ↑ Apocrypha material - pg. 04-05