As of version 1.2.1 there is a bug that won't allow you to block using Ki Blas, thus making it difficult to complete the quest. The fix is to press both buttons to block twice and then it will be enabled. This is going to be fixed in the next update. Rocketcat/Madgarden have included a push notification that alerts gamers of this. they are also fixing the bug that won't give you the achievement for getting your first Ultra Hat.