I will Answer any questions about how to make any build

[blud spillah]

well its not really about how to make a build, but i dont understand how the beserk ability works. You use it aginst an enemy and then get this thing above ur head that last for a certain amount of seconds. (1-2.4 or somthing) As you gain levels this durations goes down, not up. And while the thing is above ur head ur defense rating is at 0. But is that just the duration of how long my 0 def will last. Or do i now have to use my normal attack to get the damage boost while the swirly thing is around my head? If so, can i use concentration (what i use as a primary/left click attack). Which I thought was a good idea because while using concentration u get someone around 100+ % def rating. So i could use beserk and be hitting 450% more and have twice as much def. Or do they not work together??

someone plz answer