Toi Tsukioka is a third-year student at Koyo Academy and captain of its Futsal Club. He possesses short green hair, brown eyes, stands 181 cm tall, and weighs 64 kg. Born on December 24th, a Capricorn with blood type AB, his name references the Christmas tree due to his birthday's proximity to the holiday. He is an only child raised by both parents.

His background includes a year studying abroad in Spain, where initial language barriers were overcome with assistance from his father's friend. During this time, he prepared Japanese dishes using his mother's recipes when local food was unavailable. Skilled enough for selection to the U-18 Japan National Team, he nonetheless faced discouragement witnessing Tokinari Tennouji's overwhelming talent. Alongside Louis Kashiragi and Tokinari, he formed the "Golden Triangle" on that U-18 squad.

As captain, Toi plays the Fixo (defender) position for Koyo, wearing jersey number 1. He guides teammates like Haru Yamato and Seiichiro Sakaki, helping them overcome personal hurdles and hone their futsal skills. Initially burdened by past experiences involving Tokinari, he gradually reconciles with this history to focus on leading Koyo forward. His personal development centers on rebuilding confidence after nearly abandoning futsal and strengthening team cohesion.

His hobbies encompass fishing and learning the violin. He enjoys classical music, jazz, and traditional crafts, while disliking laziness and raw fish. He favors traditional Japanese sweets such as Anmitsu and Wagashi. His surname, Tsukioka, combines the characters for "moon" (月) and "hill" (丘), and his given name, Toi, merges "holly osmanthus" (柊) with "rely on" (依).