Character Powers or Traits are character-specific features which gives a unique buff, additional attack, or stance. Some have a cooldown period after each use, which sometimes also provide a de-buff or negative effect during the cooldown.
As per the example above, Bane's Character Power gives him additional strength every time he uses the it, up to a maximum of 3 levels, boosting the damage he can deal with dramatically. However, it gives him damage reduction after the power up as well. Notice the damage percentage differences appearing onscreen before, during, and after the power up.