Arthur is a secondary character in the story. Son of Knight Commander Roderick of Freesia. His father expected him to become a knight. Though Arthur initially gave up on that goal because he believed his Special Ability was not suited for combat. In "To a Beam of Light With You". He replaces his father, who died during the successful attack by mercenaries, as the Knight Commander.
The original timeline, Arthur was a tragic and vengeful character because of Pride's evil personality and respect for his late father. He witnessed his father's death due to a landslide that happened during an ambush planned by the bandit Val. His grief from this loss, added with Pride callously disrespecting Roderick's death made Arthur devote his life for vengeance and desire to became Roderick the Knight Commander. Thanks to this, he became a knight that even far surpassed his father. This Arthur however also developed hatred for Tiara since she is the sister of Pride and would continue to hate her until she finally healed his grief and pain.
Arthur in anime incarnation is a stark contrast of his game counterpart in which he never became a vengeful person like in the original timeline, the only similarity is his skills and respect for his father Roderick. Like the original, he was forced to witness his father nearly dying in Val's ambush but assured by Pride that everything will be alright. After watching his father rescued by Pride, witnessing firsthand the princess' kindness and desire to fulfill her promise, Arthur broke-down in tears after knowing his father's life was saved. This event made him develop a fierce devotion, respect and love for Pride, which extended to the entire royal family and kingdom. Arthur's devotion for Pride was so strong that it (ironically) became his main reason and drive to be a knight who will always be there to protect her, wherever and whenever. In addition, he developed a close bond of friendship and rivalry with Stale and the two trust each other genuinely to the point that Arthur himself is treated like a member of the royal family.
(Source: The Most Heretical Last Boss Queen Wiki)
Content compiled by AnimeList.moe from publicly available sources.
