Walking Arsenal

Walking Arsenal is an ultimate passive talent in the Warlord (Red) tree. It cannot be taken with Unbridled Rage.

In-game
The tooltip is rather misleading on what the skill actually does. Every time an attack is used that forces the Barbarian to switch to another weapon (or a pair of), for each weapon switched to, the effect of 8% increased damage applies, stacking up to 4 times and refreshing with each application. Any two skills that switch weapons are enough to maintain it at all times, similar to how Tal Rasha's Elements Set Bonus worked in Diablo III. In other words, the buff is applied per different weapon used, not per each of the 4 total weapons equipped: the Barbarian does not need to switch rapidly between all 4 of the Arsenal weapons to maintain the maximum effect.

The damage boost is multiplicative to other similar effects.