Or the unique Mesh Armor (Upgraded) with damage reduction, and the unique Vampire Gaze. A very high defense armor is also useful, as you are basically tanking mobs without a shield, consider the “Stone” runeword (Style points for using Balrog Skin or Wire Fleece). A bezerk build should use both that and shout, 1 point in each. It is not seen so often, because it overrides for example necro curses, and people prefer necro curses.

Concentration is uninteruptable and a “safe attack” when you have no shield, and Berzerk is a risky attack that lowers your defense, and you will take damageīattle Cry is a one point wonder, especially if you are going bezerk. But Concentration and more damage more dangerous Berzerk surely does work. Whirlwind doesn’t work well with Frenzy, the speed makes you fly through and not hit much. So unless you plan to hit a mob 20 times, or think you can keep the frenzy going, I would take less in Frenzy, maybe 10 points, and then fill the attacks I would use the Frenzy bonus with.

Then you can use another attack, double swing or concentration or Berzerk, and the game adds the Frenzy bonus as long as you are hasted. Yes the Frenzy builds up, so if you have 10 in Frenzy, you actually have to hit 10 times before the max is build up.

Diablo 2 barbarian builds double swing