Improvement Material (File:Screw.png) is a primary resource used for improvements in Akashi's Improvement Arsenal. Improvement Materials can be obtained through the following methods: * Certain quests reward Improvement Materials. * Some event maps reward Improvement Materials upon clearing. * Medals (File:Medal.png) can be exchanged for 4 Improvement Materials each. First Class Medal can be exchanged for 10. Present Box (File:Present box icon.png), Mackerel and Hishimochi (File:Hishimochi.png) can be exchanged for 1 Improvement Material each. * Those items can be obtained from quests, event and EO maps, and during special occasions, such as seasonal events or login rewards. * The in-game cash shop sells them in a package of 10 Improvement Materials for 700 DMM points.