Erika Myojo is a central character in the later arcs of Cardfight!! Vanguard Divinez, whose very existence is a paradox born from a shattered future. She originally lived as Hikari Myodo, the younger sister of protagonist Akina Myodo, in an alternate timeline where a catastrophic event led to her brother's death. Consumed by guilt and grief after Akina lost a critical battle known as the Fated War and subsequently vanished from existence, this future Hikari was chosen by the Fated One of Time, Liael Amorta. Her desperate wish to undo this tragedy granted her the power to travel back in time to the main series' present, setting the stage for her complex role.

Arriving in the past, she initially concealed her identity behind a fox mask, operating under the name Erika to hide her true origins from her younger brother and his friends. Her primary motivation was a singular, desperate goal: to prevent Akina from participating in the Fated War at all costs, believing that his survival was the only thing that mattered. This led her to issue stern warnings to Akina and his rival, Suo Yobitsugi, about the lethal dangers of the conflict. She even sought the help of other fighters like Taizo Kiyokura and Masanori Iseki to sabotage the tournament and eliminate Suo, whom she blamed for the tragedy in her original timeline. Her actions were driven by a heavy sense of responsibility and a belief that she had to carry the burden of saving her brother alone.

Physically, Erika is a young woman of average height with shoulder-length dark blue hair, characterized by a distinctive front streak that fades from red at the bottom to white at the top. Her personality is a stark contrast to the cheerful, albeit sickly, girl she once was. Years of loss and obsession have transformed her into a solemn, desperate, and single-minded individual. However, her core plan fails when she is defeated by Akina in a fight that forces her to confront his own resolve and belief in a better future. This defeat becomes a turning point, allowing her to begin reconciling with her past and reassessing her views on others, including a growing understanding of Suo's own struggles.

Following the resolution of the Fated War, her own timeline began to unravel. To continue existing in the present world, she was forced to fully merge with her Fated One, Gabwelius. This fusion solidified her new identity as Erika Myojo, a name that combines "Gabwelius" with her original name, "Hikari". Adopting this new persona, she decides to live in the world she helped save, changing her name to Myojo Erika and embarking on a new path as a research student for the professional Vanguard team, Kiyokura Anchor Bolt, under the guidance of Taizo Kiyokura.

Her role in the story evolves from a mysterious antagonist to a key ally and co-protagonist. She participates in the Deluxe tournament, a major competition to determine the strongest fighter, where she continues to use her signature deck from the Keter Sanctuary nation, centered on the unit Liael Amorta. Her notable abilities as a fighter are exceptional, honed from winning the Fated War in her own timeline. She is a highly skilled tactician capable of pushing even top-tier fighters to their limits, utilizing the Divine Skill of her deck with devastating effectiveness. In the Deluxe Finals, her development continues as she confronts her lingering trauma and hatred toward Suo Yobitsugi, now a fellow competitor. With the encouragement of Gabwelius's will within her, she finally faces these deep-seated emotions head-on, signifying her final step toward healing and fully accepting her new place in the world.