The dash button does not exist originally, I was hoping it may encourage player to move around and keep distance from the boss so the player can rest for a while. If not, the boss will just keep attacking you.
I have tried to make the dash allows you to pass through enemies but the problem is you would be able to attack the boss for 4 or 5 times while the boss is attacking the other way. The parry window is around 0.3 sec.