Not much is known about Claudia's childhood save for the fact that both her parents were killed in a demon swarm (she never specifies where she came from) and the most that Nero could get out of her is that the scar is due to a traumatizing near death encounter with a demon. Later on in Anamnesis, they find out that Claudia is one of the few survivors of the once grand Libera City and that her parents were fast growing researchers that were killed in the Libera City Massacre nearly ten years ago.

As a child, Claudia is very petulant and awkward, craving love and attention but not getting enough of it from her parents. Due to her parents' positions in her city, Claudia was almost always excluded and outcasted, though it is more of apathy than outright malicious bullying. This has caused her to become extremely wary and distrustful of new people she meets, often voluntarily distancing herself to avoid getting attached and hurt. Despite not receiving much love and care, however, Claudia loves her parents and wanted their approval and attention. This had led to her participating in most of their research towards Project CASS and is part of the reason why Libera City falls to a demon siege.

During the fall of Libera City, Claudia was tasked by her dying mother to leave their home with an experimental Golden Orb. With her father dead and mother at death's door, she obeys and runs away, not looking back. A demon manages to catch her off guard as she was escaping the city walls and slashes her face, hence the scar. The demon would have finished her off if not for a passing Vergil examining the ruckus happening in the city. He unintentionally saves her from the raging demon to sate his curiosity but leaves her nonetheless once the job is done. The subsequent release of his devil trigger along with the experimental golden orb's activation fused itself onto Claudia's scar and eyes, reviving her and enhancing her marginally. Her myopia disappears and her stamina and strength received a boost, though it would be some time before she realizes this.

Leaving Libera City, Claudia is passed from various different orphanages in different cities. She never stays long due to her 'creeping out' most of he kids and facility from her unnatural eyes, scar, and indifferent attitude. They found her off-putting and terrifying, therefore ostracizing her and isolating her. This continued on up until she reached fifteen years old, as she runs away from the last orphanage she is transferred to and applies herself to a local research institute specializing in demonology. A kind man realizes her potential and allowed her to work for two to three months. The man then connects her to Agnus in Fortuna City, knowing that she'll develop much further in research there. Agnus realizes who her parents were and their research coincides with his so he accepts her and sponsors her stay in Fortuna City, two years before the start of the events in DMC4. She meets Nero there as he was originally the assigned escort and guard to her by Credo. Claudia didn't want to interact with her 'bodyguard' more than what was necessary but his aura intrigued her and she realizes the familiarity of it compared to her savior. She never says anything about it to Nero, thought she subtly lets him know that it doesn't matter what or who he is once they became actual friends.

During the events DMC4, Claudia simply acts as Nero's NPC support and follows through his story. When Nero fully gets his arm merged with Yamato, however, Claudia adamantly tells him that he will follow him despite the danger lurking (and quite frankly, her boss is more likely crazy at that point, so she's really much safer with him). She says that because they are friends and that the arm is an important research material that could potentially help others. Later on, she does meet Dante in the forest and also realizing how similar his aura is to her savior (and to Nero) back in Libera City, she questions him. To her dismay, he deflects her questions and simply comments on Nero "taking care of his nerdy girlfriend" to their embarrassment. After the Order's downfall and Nero's defection, Claudia follows him and Kyrie to their new home, defecting from the Order as well.

Her escapade with Nico in finding certain Order documents has her learn that the man who took her in during the few months she ran away from the orphanage has passed away from a demon attack.

Anamnesis occurs two months after the events of Devil May Cry 5. It tells the in-depth story of Claudia's past, as the events in this game will happen in the ruined city of Libera, Claudia's now revealed previous unknown home. Parts of some missing info from Tasha's history during the events of DMC4 are also hinted and explained as well.

The DLC-sequel shows the story of Claudia's childhood and what happened during the fall of Libera City. There are also segments wherein the players may explore odd notes and random papers from an unknown scientist (assumed to be Agnus' former henchman, possibly investigating the lost research found in the ruined city) detailing parts of Tasha's past. Most of the missions are fast-paced and the story-driven parts are given through various flashbacks from each hidden Golden Orb found and acquired. This also marks the return of Claudia and Tasha as playable characters from the Mission Interlude: Left Behind DLC of DMC5. Compared to the previous DLC, they are now a more proactive playable character in the game with taunts and a new mechanic present.

The main story and other information regarding Anamnesis can be found here. Be wary of spoilers as the DLC is post-DMC5 and will therefore mention spoilers from it.