Unforgiving: Instead of losing 1 Fury every 2 seconds, you gain 1 Fury every 2 seconds.
Unforgiving is a huge tool for Fury-flow Barbarians. It allows you to be sure you’re going to start every fight with some Fury, and if you’re a little patient between fights, can ensure that you’ve got full Fury. Sadly, while it’s still pretty cool for most other Barbarians, there remain more useful things that are aligned with the skill selections other Barbarians are going to be making. If you feel like you can spare a passive skill slot for something, though, this should be your choice- unless you find yourself with full Rage most of the time anyways. Don’t scoff- it’s possible. In that case, you might as well take Berserker Rage instead. Just don’t be too eager over this if you’re not having trouble keeping your Fury up.
Boon of Bul-Kathos: Your Rage skill’s cooldown is reduced by 30 seconds.
This is simply insane. The most drastic effect will be with The Mountain’s Call, as together they can reduce Earthquake’s cooldown to 75 seconds. But with the ability to make Wrath of the Berserker last extra long, ragestream Barbarians are unquestionably going to love putting this with that. It certainly doesn’t hurt critical-hit Barbarians either. This is most important for Barbarians who focus on pulling things in to kill them with Earthquake, though- getting a cold Earthquake every 90 seconds or a regular one every 75 is an immense upgrade, and will let you handle far more battles far more quickly. Even those Barbarians using Call of the Ancients are going to find this skill to be an amazing boost- tanking Barbarians may not find it worth the slot, though. A tank, after all, needs to stay stable more than it needs to turn awesome for 15 seconds at a time. Not so say it should be discounted entirely, that’s still 1/6 of the time if Striding Giant is used as often as possible.
The selection of passive skills for a Barbarian is about two-thirds straightforwards. Whatever it is that you plan to do with your Barbarian, there are usually two obvious choices to make for your Passive Skills. The third skill is always a stickler, and you should make your choice based on your playstyle and your playing experiences. If you find yourself running out of rage a lot, then you should probably take Unforgiving or Animosity, even if they’re not recommended for what you’re doing. If you run low on life frequently, or find yourself dying just before you can finish off the enemy, then you need Relentless, Tough as Nails, or Nerves of Steel. If being stopped from doing what you want for even a few minutes throws your combat scheme completely off, then you should have Juggernaut. Even Pound of Flesh can have its place, if you find yourself healing off of health globes frequently. Nothing can be completely discounted- but some things are more likely to be of use to you than others.