I just want to ask, for what is this rage points we acquire while we are using a certain skill? Please refer to the attached picture for example skill. Some skills also acquires rage points.

I had the same question and opened a post in bug section. No reply from any of the berserkers out there to help push this fix, or from the devs.

 

From what i heard apparently the rage bar will appear along with the 11th skill of the berserker. I think until then they just don't care and will wait for that pach....