Carrera

Carrera (カレラ), also known as Jaune (原初の黄), is one of the Primordials that joined Tempest after Diablo recruited her. She serves as the Chief Justice Officer of the Supreme Court in Tempest as well as a leader of the Black Numbers along with Testarossa and Ultima and is counted as a member among Rimuru's Twelve Guardian Lords.

Appearance
Carrera assumes the appearance of a young woman with shoulder-length blonde hair and blue eyes. She wears a black snow coat with a skull pin over a white shirt and tie. Her appearance gives off the vibe of a high school delinquent. She is slightly taller than Ultima but shorter than Testarossa.

Personality
Just as her appearance suggests, Carrera possesses the personality of a high school delinquent. She is carefree, energetic, and exhibits a love for engaging in battles, often unleashing her Nuclear Magic for sheer enjoyment. Additionally, she tends to be egocentric and has a tendency to become easily angered, rarely taking others' opinions into consideration. While she can be arrogant, Carrera is capable of recognizing formidable opponents, as demonstrated during her encounter with Tatsuya Kondou.

While engaging in a fight with Kondou, she realized that she had underestimated humans to a significant extent. This realization prompted her to quickly reassess her attitude and confront him seriously. Carrera developed a notable amount of respect for Kondou when he proved capable of holding his ground and matching her power. Despite her lineage being infamous for being unyielding in negotiations, she accepted Kondou's powers and soul as part of a deal to fulfill his wish of assassinating the emperor.

Background
Carrera, like her other primordial brethren, was born during the dawn of time before the creation of heaven and earth as the demonic counterparts to the Seven Angels of Origin split from the Great Spirit of Darkness. Her and the other primordials ruled Hell undisturbed for an eternity with Rouge as its overlord. When Bleu and Vert were resurrected completely loyal to Rouge after their attempt to overthrow him, Carrera, Blanc, and Violet agreed to never fight each other directly, instead preferring to outsmart each other in things like games and who could incarnate in the material world first.

Hundreds of years ago, before Diablo recruited her, she created a powerful life-form in a small country in Sorcerer's Dynasty Sarion but it was taken down by Leon Cromwell in his days as hero. She was frustrated, unaware that it was Violet who led Leon there. As a result of this, she spent all of her time developing flashy and powerful magic as vengeance for Leon's interference. Leon's knights tried negotiating with her multiple times but they were ignored each time. Worse still, she caused them a great deal of trouble by firing nuclear magic upon their city on a near daily basis as a provocation to Leon so he would challenge her to a fight since Guy acknowledged his strength.

Trivia

 * She was named after the car.
 * She was shown in The Ways of the Monster Nation spin-off manga in chapter 42 and in short comic by the end Light Novel Volume 13 drawn by Taiki Kawakami himself.
 * Among all Primordials, she has arguably the worst reputation between Demon Lords due to her unpredictable and destructive nature.