Dual Blade book event question I want to say a long time ago, they did a similar event. But, the skill books expired if you didn't use them. Do the skill books you get for Dual Blades expire? If they expire, how long do you have until they expire? The books are as follows. All of them have 100% chance to raise the Master Level of their corresponding skills. Lv. 30: Slash Storm 20 Lv. 55: Flying Assaulter 20 Lv. 70: Mirror Image 20 Lv. 80: Shadow Meld 20 Lv. 120: [Special Mastery Book] Blade Fury 30, [Special Mastery Book] Thorns 30