Barbarian abilities and multi-classsing into an Imitating Barbarian.

[Chess Pwn]

So my question is how would Barbarian abilities like "Terrifying Visage (Ex)" work if you multi-classed into wild stalker or Viking? Both of those say at lv four your barbarian level is their class level minus three. So If I was a Scarred Rager 2 and Viking 5 (effective barb 2) would I add 1 or 2 on my Intimidate checks? I see it stacking because the posts say that these levels stack for Rage Powers, so why not stacking for these abilities?

Terrifying Visage (Ex):

A scarred rager adds 1/2 her barbarian level on Intimidate checks against humanoids who are not members of barbarian tribes. When dealing with barbarians, the scarred rager may choose to add this bonus on Diplomacy checks instead. The DC of any fear effect created by the scarred rager also increases by 1.

Viking:

At 4th level, a viking gains the rage ability as the barbarian class feature, but her barbarian level is considered to be her fighter level –3.

[Mauril]

The Viking ability "Beserker" says that you gain rage equal to a barbarian of your level -3. It does not say that you become a barbarian at your level -3. Your viking levels only stack with your barbarian levels for the purposes of rage. It's unclear if this is just for rage rounds, or if this applies to rage powers as well, but as the Rage Powers feature at level 6 says that you can gain rage powers every other level, I would argue that the two classes stack for determining the level of rage powers you can take.

The reasoning is simply because RAW doesn't say that you do. The bigger reason is that two classes' abilities don't stack unless they specifically say that they do. Often, archetypes don't stack well with other archetypes for this reason. Archetypes are supposed to be niche versions of a specific class and, as a result, don't stack well with other classes that they aren't specifically designed to stack with. Two archetypes from two separate classes have an even harder time stacking with each other.

Basically, Vikings are modified Fighters, Scarred Ragers are modified Barbarians. Barbarian and Fighter levels don't usually stack for stuff, so it would have to be called out as an exception to that general rule for Vikings and Scarred Ragers to stack for stuff.

[Chess Pwn]

It's just to me that if the Barbarian levels are stacking to qualify for Barbarian level rage powers, why wouldn't they stack for other Barbarian abilities? And Terrifying Visage was an example, the Normal Barbarian has trap sense that would fall under the same situation. But ya, it's interesting cause the wording seems the same for rage powers and other things, just keying off barbarian level. Also cause in the Berserker ability it doesn't say "effective barbarian" like it does for animal companions and druids and in the inquisitor's anger Inquisition.

Divine Anger (Ex):

: At 6th level, you gain the ability to rage like a barbarian. Your effective barbarian level for this ability is your inquisitor level – 3. If you have levels in barbarian, these levels stack when determining the effect of your rage. You do not gain any rage powers from this granted power, though if you have rage powers from another class, you may use them with these rages. You can rage a number of rounds per day equal to your Wisdom bonus, plus 1 round for every inquisitor level above 4th.

But I see that since it doesn't say it's safer to say it doesn't

[Mauril]

It's pretty clear that the ability grants rage, not the ability to stack with every barbarian ability. It's like the Kensai Magus's ability to take fighter only feats. The ability stacks only four the purpose of qualifying for feats, not for increasing Bravery or Weapon Training or any other Fighter ability that scales. Ultimately, it's a case of the burden of proof lying on it stacking rather than on proving it doesn't stack.

[Quandary]

I'm pretty certain they don't stack.
Viking/Wild Stalker stack with/are considered Barbarian levels for Rage, and Rage Powers are somewhat of a sub-set of Rage, but that doesn't let them count class levels towards other Class Features that they don't grant or even acknowledge. Terrifying Visage isn't a Rage Power, it doesn't even require that you be Raging (although that metric isn't actually relevant, it COULD apply only during Rage yet still be distinct from Rage/Rage Powers).

This should work similarly to if you m-classed Viking/Wild Stalker with real Barbarian that has Improved Uncanny Dodge: the V/WS levels would not count towards "Barbarian Level" to determine whether you can be Flanked or not (unless you also are gaining Uncanny Dodge from those multi-class levels, per normal rules for IUD).

Any levels from actual Barbarian class (Archetyped or not) also don't count towards other Class Features (besides Rage/Rage Powers) that Wild Stalker/Viking may gain that function off the Class Level of Wild Stalker/Viking.