The first skill in the Berserkers tree is A Capacity for Rage. This is the exact same skill as the Human alignment skill Quick to Anger. When capped, it grants you a 154% increase to the speed that you gain combo meter. When combined with Quick to Anger, you will earn combo 308% faster than normal! Also, each of these skills has an additional benefit. When capped, they grant you an additional combo level. So if both of these skills are capped, a Berserker can have 5 combo levels. This skill is shared in co-op too, so the Champion you are playing with will now have an added combo level. For the melee intensive Berserker, serious consideration should be given to maxing out this skill.