Rebecca is a teenage girl of average height and has a slender, curvaceous build. She has long, wavy red hair and navy-blue eyes.
During the date, she wears a necklace with a long, elegant dress, and a white short-hood over her shoulders. After returning to her home, she wears a common white dress with a dark robe over her shoulders.
When she meets Asta at first, she comes off as distant and reserved while confronting him. However, after Asta defends her and gains her trust, she warms up as a very kind and outgoing young woman.
She cares deeply about her siblings, so much that many mistake them for her own children. Rebecca is willing to take on the job of a maid at only 16 to provide for them.
Rebecca has three brothers and two sisters. She has been taking care of her siblings, since she was young.
One day, her friend, Erika Sitate, convinces Rebecca to join her and Helene Barbary on a group date, where Rebecca is paired with Asta. She is disinterested at first, but the two bond over being elder siblings. When a drunkard harasses Rebecca, Asta protects her and the couple runs out of the restaurant. In an alley, Rebecca asks if Asta likes someone and invites him to meet her siblings.
Another day, Rebecca is watching Asta play with Luca, Marco, and Marie Adlai when Gauche Adlai arrives to visit his sister. Rebecca has to comfort Luca after she is scared by Gauche's threatening manner. After Sister Theresa takes Marie back to the church, Rebecca invites the two Black Bulls back to her house for the night. She makes dinner for her family and the Magic Knights, and as she is cleaning up, she is embarrassed by her siblings' questions regarding her feelings for Asta.
After being woken up by Asta and Gauche's fight, Rebecca runs to tell them that Luca and Marco are missing. She is further worried when she hears similar shouts from nearby houses. Noelle Silva comes forward and reveals that she saw the children walk out of the town, and Theresa explains that the snow is magical. Rebecca asks Asta to save her siblings, which he promises to do. Asta, Gauche, and Theresa fly away, leaving Noelle with Rebecca.
They return to Rebecca's house and Noelle reports the incident. Rebecca then cooks some food for her siblings and Noelle and voices concern over Asta's well-being, but Noelle assures her that he will come back with the children.
Some days later, the Black Bulls visit Nairn, and Rebecca watches Marco return Asta's squad robe. Accepting that she cannot stand with Asta in battle like Noelle can, Rebecca kisses Asta's cheek and thanks him for saving her sister and brother.
Months later, Rebecca attends the Star Awards Festival. When the Black Bull is ranked as the second best squad, the crowd questions the result, but Rebecca attests to the squad's accomplishments. She also cheers on Asta when he takes the stage, and she is frustrated that the crowd still doubts him.
A few weeks later, Rebecca and her siblings are saved from Patolli's Arrows of Judgment when Julius Novachrono stops and reverses time. Days later, after the attack from the elves, Rebecca runs to Theresa to show her the newspaper article about Asta's trial.
Six months later, a demon attacks the Clover Kingdom, and when some citizens mistake Asta as a devil helping the demon, Rebecca corrects them that Asta is there to protect the kingdom. She cheers after Asta cuts apart the demon.
She develops romantic feelings for Asta after a drunk man starts insulting her and attempts to forcefully claim her. This leads to Asta defending her from the drunkard, protecting her well-being. She later kisses Asta for saving her siblings.
They both have lived relatively similar lifestyles - growing up without parents, and having brothers and sisters.
Noelle and Rebecca develop a small rivalry over Asta, when they first meet. They do eventually get along during the children rescue mission. After the mission, Rebecca kisses Asta as thanks for rescuing her siblings - to Noelle's dismay.
Erika is friend of Rebecca's who convinces her to participate in a group date.
- Rebecca's favorite things are her siblings and cooking.
- Rebecca ranked #29 (tied with the Witch Queen) in the first popularity poll and #22 in the second.
- Rebecca is the second best chef in the series.