Hiroyuki Ito began his career with Square debugging and creating sound effects for the first three installments of the Final Fantasy series. He was assigned the role of Battle Designer for Final Fantasy IV, and created the Active Time Battle (ATB) system. He has been responsible for almost all the gameplay systems in the series, including the Job system in Final Fantasy V, the Relic system in Final Fantasy VI, the Materia system in Final Fantasy VII, the Junction system in Final Fantasy VIII, the Ability system in Final Fantasy IX, and the Active Dimension Battle (ADB) system and Gambits in Final Fantasy XII. He served as director of Final Fantasy VI alongside Yoshinori Kitase, and took on the solo role of director with Final Fantasy IX. He was initially.directing Final Fantasy XII alongside Yasumi Matsuno, but then later with Hiroshi Minagawa when Matsuno left the project due to sickness.