Akina Myōdō is the protagonist of Cardfight!! Vanguard Divinez and its sequel arcs, including Parallactic Clash Arc. He is introduced as a second-year high school student who later advances to third year. Akina lives with his younger sister, Hikari, and their father, who is often absent due to work obligations. Because Hikari has a frail constitution and is frequently hospitalized, Akina shoulders significant domestic responsibilities and acts as her primary caregiver, a role he has taken on with deep dedication.

Akina possesses a selfless and nurturing personality, always prioritizing the well-being of others before his own. This caring instinct extends beyond his family; he is naturally sociable and shows great kindness to his peers, such as when he insists on walking home with a classmate, Suo Yobitsugi, through the rain to ensure he stays safe. Akina is also persistent and wholeheartedly committed to his goals. Once he learns of the Fated Clash tournament, where the winner can have any wish granted, he becomes determined to enter and win in order to cure his sister's illness. This determination is fueled by a sense of guilt, as he believes he was responsible for the mountain accident that led to Hikari's condition.

At the start of the series, Akina has no experience with the card game Vanguard. His interest is sparked by Hikari and by his senior at his part-time family restaurant job, Nao Inabe. After being chosen as the owner of the Fated One of Miracles card by the mysterious, plush toy-like entity Gabwelius, Akina asks Nao to teach him how to play. She mentors him in deck building and fighting strategies, and he quickly develops his own aggressive playstyle. As a cardfighter, Akina uses a Keter Sanctuary deck built around his main unit, the Fated One of Miracles, Rezael. His strategy focuses on relentless offense, maximizing the use of Critical Triggers and utilizing Rezaels Divine Skill to shuffle triggers back into the deck and perform multiple drive checks. He also possesses a power known as Design Force, which allows him to manifest miracles during fights and resist supernatural interference.

Throughout the Fated Clash, Akina grows significantly as a fighter, defeating experienced opponents through sheer willpower and adaptive tactics. A pivotal moment comes when a future version of Hikari appears to warn him that his original fate was to lose the finals, which would result in his death and the destruction of the tournament stage. Despite her pleas for him to quit to save himself, Akina refuses, believing that he can defy destiny. He ultimately wins the tournament, uses his wish to permanently cure Hikari, and helps his rival Suo begin to heal from past trauma. Following these events, Akina continues to play Vanguard, eventually discovering his own personal dream of becoming a professional fighter.

Key relationships define Akinas journey. His bond with his sister Hikari is the emotional core of his character, driving his initial motivations. Nao Inabe serves as a crucial mentor, teaching him the game and supporting him both on and off the battlefield. He develops a complex friendship with Suo Yobitsugi, who transforms from a fatal rival into a close friend who insists on daily cardfights. Gabwelius acts as his guide into the supernatural conflicts surrounding the cardfights.

In the Parallactic Clash Arc, Akina faces a new crisis. An abnormal phenomenon known as Fantasma has shrouded the town of Kaga in fog, transforming it into a distorted version of itself. Now a third-year high school student, Akina continues to demonstrate his selfless nature, rising up to restore Kaga to its original form. He steps forward as a Mythisch Fighter alongside his allies Nao Inabe and the former champion Michiru Hazama to confront this new threat.