Odion, known in the Japanese version and manga as Rishid, is an adult character in the Yu-Gi-Oh! anime who serves as the adopted older brother of Marik Ishtar and Ishizu Ishtar. He was abandoned as a baby in the desert by his birth parents and was found by the tombkeeper's wife, who took him in and raised him as her own. His adoptive mother loved him deeply, and the childless Ishtars initially considered him their heir, but his adoptive father never fully accepted him and treated him only as a servant. This strict and harsh upbringing left Odion scarred both physically and emotionally, yet it also gave him a profound sense of duty, endurance, and loyalty to the Ishtar family.

Odion appears disciplined, restrained, and serious, often seeming cold or distant to others. Beneath this reserved exterior, he is deeply caring and fiercely devoted to the people he loves, especially Marik. He is an honest duelist who believes in fair competition, and he demonstrates sharp tactical intelligence, calm analytical thinking, and the ability to anticipate the moves of his opponents. His most prominent trait is his unwavering loyalty, which leads him to endure mistreatment and sacrifice his own wellbeing for the sake of his brother.

Odion's central motivation is protecting Marik and trying to keep him from being consumed by darkness. He carries the weight of a painful family secret: when Marik and Ishizu secretly left their home to go to Cairo and Odion covered for them, their father threatened to punish Odion for it. The distress of that moment awakened Marik's evil alter ego, Yami Marik, who murdered his own father with the Millennium Rod and nearly killed Odion as well. To spare Marik from the horror of the truth, Odion instead led him to believe that the Pharaoh was responsible for the death. Odion then chose to follow Marik willingly, both out of his vow of service and in an effort to keep Yami Marik from gaining complete control.

In the story, Odion acts as a Rare Hunter and the most trusted servant of Marik during the Battle City arc. He disguises himself as Marik during the semifinals and duels Joey Wheeler, and when he reluctantly summons the Winged Dragon of Ra, he is unable to control the divine beast and falls into a coma. His incapacitation allows Yami Marik to take full command of Marik's body. During the finals of the tournament, Marik's soul reaches out to Odion, begging for forgiveness and saying a final goodbye, and those words revive Odion from his coma. He then makes his way to the island tower and gives Marik the confidence and inner strength needed to reclaim his body and defeat his evil half, allowing Marik to find redemption.

Odion's development shapes him into a selfless protector who rises above his role as a mere servant. He begins as a mysterious and seemingly ruthless figure but is gradually revealed as a man driven by love for his family and a desire to save his brother from the darkness that plagued their house. His most meaningful relationship is with Marik, whom he serves without reservation, and he also shares a respectful bond with his sister Ishizu. His presence also serves as a quiet counterweight to Yami Marik, the cruel personality he spent years trying to contain. After the conflict concludes, Odion leaves with Marik and Ishizu to start a new life, having fulfilled the family's ancient oath to the Pharaoh.

Odion is a skilled and resourceful duelist whose deck relies on Trap Monsters, such as the Embodiment of Apophis, allowing him to set clever traps and outmaneuver opponents while still dueling fairly. He is physically resilient, strategically experienced from years of training, and marked with the tombkeeper's symbol on his face as a sign of his place in the Ishtar family's sacred duty. His greatest contribution, however, is his loyalty and strength of will, which ultimately help his brother overcome the darkness and find peace.