Lucrecia, một trong số nhà khoa học của Shinra, làm việc như một trợ lý của cha Vincent , tiến sĩ Grimoire Valentine. Trong thời gian kề cạnh Grimoire, họ đã tìm ra hai Vũ khí được phát triển Planet, both used as part as the Lifestream's emergency function. Cùng nhau, Grimoire and Lucrecia were able to discover the Crystal Cave, where it was thought Chaos would awaken at the appointed time. Grimoire, however, was killed in an attack by the newly discovered Chaos, and Lucrecia's research was discarded as pure nonsense.
Later on, Lucrecia was appointed to work on the Jenova Project along with Gast and Hojo. Trong thời gian này, Vincent Valentine, một thành viên của the Department of Administrative Research (sau được biết như là Turks), was assigned to supervise the project. Lucrecia immediately recognized Vincent as con trai của Grimoire, and was quite shocked that Shinra would assign the son of her deceased mentor to supervise her. In spite of this, she still warmly welcomed him, and even began spending time with him when the two were off work, although she kept the fact she even knew his father a secret. Over time, Vincent and Lucrecia seemed to have either become romantically involved, or close enough that they were near that point. However, this all fell apart when Vincent found a document pulled up on Lucrecia's computer telling of her time working with Grimoire. When Vincent confronted Lucrecia and asked her why she never told him about this, she revealed to him she was the one responsible for his death. Vincent — not seeming to think Lucrecia was responsible as much as she did — attempted to counsel her. This attempt was in vain, as Lucrecia felt even more guilty for Grimoire's death than she did before. This put a strain on Vincent and Lucrecia's relationship, causing her to seek Hojo for comfort.
Lucrecia became romantically involved with Hojo and eventually married him. Trong thời gian này, cô đã mang thai và đồng ý để đứa con chưa chào đời của mình cho mục đích nghiên cứu. Hojo injected both the pregnant Lucrecia and her fetus with Jenova cells. However, the cells had an unexpected side effect: Lucrecia would have visions of her son, Sephiroth, and of the future atrocities he would commit. The visions were extremely painful and Lucrecia often collapsed in pain, much to Vincent's despair.
When Vincent tried to confront Hojo about Lucrecia's condition, Hojo mortally shot him and used his corpse as an experiment, only to label him as a failure and discard him. Lucrecia, devastated with Vincent's death, used her knowledge about Chaos to resuscitate him by infusing pure mako into his body. The procedure worked, as Vincent's body, due to Hojo's previous experiments, was strong enough to become a Chaos vessel. However, Chaos was completely out of control and only stopped when the Protomateria had a reaction to it. The Protomateria, which Grimoire had discovered and which Lucrecia theorized to have been created by the Planet "out of necessity as a means to control Chaos and prolong its own inevitable fate", had been in Lucrecia's laboratory. She put it inside Vincent's chest, and thus Vincent was able to control Chaos to a degree. Unfortunately, while it halted Vincent's decay, it did not resuscitate him.
At some point around this time she gave birth to Sephiroth, but the child was taken away without Lucrecia even being allowed to hold him. Hojo either left her, or she left him shortly afterward. Overcome with sadness and sorrow, Lucrecia tried to kill herself, but not before she left her thesis about Chaos and Omega for Vincent, who was still unconscious. Thereafter, due to the Jenova cells in her body, Lucrecia was unable to truly die. She left her old life behind, seemingly vanishing without a trace. It is unknown where she went immediately following her desertion of Shinra, but she eventually ended up in the Crystal Cave, back where it all began.
Vài năm sau, khi hành tinh đã phải đối mặt với sự diệt vong do bàn tay của chính con trai mình, Lucrecia một lần nữa được tìm thấy bởi Vincent khi anh ta đang du hành với nhóm của Cloud . Attempting to approach her, Lucrecia warned Vincent to stay away from her. It is then that the events of what had happened with Vincent and Lucrecia are recounted for the rest of the party (and for the player). Lucrecia went on to say she felt so much guilt for all that she had done she wanted to disappear; she did not want to be with anyone and she wanted to die. Lucrecia then told Vincent she had been dreaming about Sephiroth a lot lately, and asked him if her son was still alive. Vincent, who did not have the heart to tell her of all the horrible things that Sephiroth had done — and was planning to do — told Lucrecia that Sephiroth was dead. Later, when Vincent revisited the cave, he found an unconscious Lucrecia. His memories of her, however, somehow caused Chaos to awaken inside of him.
She lingered on in the Crystal Cave until the events of Dirge of Cerberus -Final Fantasy VII-. In a major event in Dirge of Cerberus, the unification of Lucrecia's data, it is speculated she had feelings for Vincent. This is made abundantly clear throughout the game, but even more so during the seemingly random words flashing across the screen, during which she says "Vincent" and "I loved..."
Following Omega's destruction, Vincent spoke to Lucrecia, thanking her and telling her she was the reason he survived. A tear can be seen rolling down Lucrecia's cheek as Vincent leaves the cave.
Lucrecia is a Spanish name and is a reference to the mythical Roman figure Lucretia, who was infamously raped by Sextus Tarquinius. It is possible this allusion is a hint that Lucrecia's relationship with Hojo was less consensual than it appeared, or it could simply be meant to emphasize the perverse nature of Sephiroth's conception.
The name Lucretia comes from lucrum, meaning "wealth."
In Final Fantasy VII, Lucrecia was not given a last name. Her last name in Dirge of Cerberus, "Crescent", is a surname that was reused from Final Fantasy IX's character Freya Crescent. The word "crescent" is also derived from the Latin word that means "to grow," and one of her key plot points was Sephiroth's growth in her womb.
- Lucretia can be the name of a Viera character in Final Fantasy Tactics Advance. Names for most characters are chosen at random from a pool of names.
- In Dirge of Cerberus, Lucrecia's birthday was revealed to be July 22, and her bloodtype to be B.
- Dirge of Cerberus contains some concept artwork for the picnic basket she carries to Vincent in a particular flashback, and the concept artwork quite clearly shows the basket containing red wine. The opening FMV sequence shows a wine glass in Vincent's room containing a red liquid some decades later.
- The ponytail of her "crystallized" model is several inches longer than that of her "scientist" model, indicating that her hair, like Vincent's, has grown during this time.
- Interestingly, she shares a physical similarity to Yuna from Final Fantasy X, as well as a very similar voice, despite the fact the two characters have different voice actors.
- In the Early Material Files included with the Ultimania Omega guide (scenes and ideas that were ultimately cut or changed in the final product of Final Fantasy VII), Vincent's section mentions that Lucrecia was originally "on Vincent's side," drugged by Hojo, and forced into experimentation against her will. However, in the game's final version (and Compilation canon), she was clearly a willing participant, though she also shows signs of turmoil over choosing such.
- The Early Material Files also mention that she was considered an "idol" in the lab, and was the only female on Hojo's team.
- If one looks closely in some of the Dirge of Cerberus cutscenes, one can see Lucrecia has a pair of silver dagger earrings, similar to those of musician Gackt, who not only contributed "Longing" and "Redemption" to the game's soundtrack, but also served as a model for Genesis.