This is a guide to explain how to actually unlock the final chapter in Story Mode "Wind of Light".

The following conditions must be met in a single playthrough of Story Mode (Does not work if you do it via EX/Bonus mode):

• Must have REX Armor on all boss fights by building a full OZ Gauge meter before entering the boss fights (Chapters 12, 14, 16 , 18; for chapter 19 you will automatically be granted REX Armor).
• Must finish all the same boss fights with at least a LVL 2 Deathblow (LVL 1 Deathblows sometimes do not count so don't rely on these)
• Must attain at least an A rank on all stages (not just the overall result)

If you fill all these requirements, after you beat chapters 19's boss, you will instead be thrown into a Save game prompt, this will be a confirmation that you successfully unlocked chapter 20.