It's your supercharge meter. When it is full it affects some of your powers by making them more powerful or adding a knockdown or other effect. There are also certain powers that need 25, 50 or 100% of it. You charge it up but doing weapon attacks or breaking open the barrels that give you health.
My power is discombobulatingly devastating. I could feel his muscle tissues collapse under my force. It's ludicrous these mortals even attempt to enter my realm
I can't remember the exact name for it, but it's your super ability. Some of the attacks or powers that you unlock require so much percentage of super ability to use. For example, one of the powers I unlocked under the telekinesis side uses 50% of that super ability meter. You fill up the meter by attacking enemies and getting combos I believe. I hope this helps!
XBL Gamertag: Alter Ego 83~~~~PS3 Gamertag: Alter_Ego_83 http://gamersonarant.blogspot.com