Light Tsukiko is one of the Four Heavenly Kings and friend of Protagonist in the Nintendo 3DS game Yu-Gi-Oh! Duel Monsters Saikyo Card Battle.
Saikyo Card Battle
She mets Protagonist at the beginning of the Legendary Challenge tournament where she gets interested on him. She'll help Protagonist "study cards" to hang out with him. She also calls him (onii-chan) despite having a real brother, Dark Kuroda nNii-san). She joins the Legendary Challenge tournament to win the Phantom rare card prize but later sets on the mission to win the tournament to go on a date with Protagonist.
She's calm and polite most of the time but seems to have a double personality disorder. While Dueling, her face becomes twisted, her face changes and laughs maniacally. She returns to her calm self when she wins or her LP reach 0.