The information processing device according to the present invention fuses a basic first game content and a second game content used as source material for fusion before a preset condition related to fusing the first game content and second game content is satisfied, thereby varying the upper limits of parameters configured in the first game content in a stepwise manner, and, once the preset condition is satisfied, initializes the parameters configured in said first game content while at the same time providing items capable of increasing at least the initialized parameters configured in said first game content.