Do creatures with multiple arms (4+) get to make a standard attack with each pair?

Question

I am working on a character design who will have 4+ arms. I am planning on having the character wield multiple weapons and was going to focus on full attacks and two weapon fighting. Then I read a guide discussing vital strike and how when used properly it can deal significantly more damage than multiple iterative attacks and critical hits. So I am looking into ways to have the same 4+ armed character use a standard attack with each pair of arms to benefit from vital strike.

However the issue is that I do not know multiple arm rules and combat rules well enough to know if this is possible. When I read the combat rules for two weapon fighting and the feat TWP neither say what kind of actions they are. Which to me suggests that a character can perform two weapon fighting as a standard attack without using a full attack. But since flurry of blows and a full attack both use full round actions maybe I have only ever seen it being used in a full round action. To be honest before I started working on this I thought TWF was always a full round action.

I found this wonderful feat which is designed for monsters with 4+ arms which takes the place of two weapon fighting and also suggests the same as above. The feat is multiweapon fighting.

Am I correct in that a 4 armed character could wield two 2-handed weapons with both weapons taking -4 on attack rolls and each could make a standard attack which benefits from vital strike in a round? Also using light weapons would increase the number of attacks but would still be made at -4 as the feat says nothing about light weapons being reduced to -2 like TWF does.

Answer 1

Multiweapon Fighting, along with very-nearly every source of bonus attacks in the game, requires a full-attack. A full-attack is a full-round action in which you can make several attacks, e.g. from iteratives, extra arms, extra natural attacks, haste, and whatnot.

Vital Strike offers a special standard-action option to make one attack, and deal extra damage.

You cannot use a standard-action option and a full-round-action option at the same time. Even if you had extra standard actions somehow, at best you would use Vital Strike, and then use a regular full-attack.

Thus, you cannot take advantage of extra limbs when using Vital Strike. Multiweapon Fighting only benefits you when using a full-attack. And since Pathfinder lacks the Savage Species rules for four-armed weapons and the like, it’s impossible to benefit from more than two arms with Vital Strike.

Also, for the record, that guide is wrong. Vital Strike simply cannot keep up with full-attacks. At best you combine the Greatsword Battler divine fighting technique with pounce to arguably use Vital Strike and then full-attack too, which is solid enough until you start trying to figure out how on earth you are going to get pounce as well as all those feats (vivisectionist or synthesist are your only real hopes so far as I can tell).

Answer 2

The rules for this are actually up in the Standard Actions section, under Attack -> Multiple Attacks

A character who can make more than one attack per round must use the full-attack action (see Full-Round Actions) in order to get more than one attack.

So, despite having 4 arms, you still need to take a full attack in order to get more than one attack per round.