So the arm by itself isn't bad granting you the means to hold an extra item or a shield while two weapon fighting or fighting two handed.
However my question would be does it qualify you for multiweapon fighting -- and if it does do you now gain extra attacks from the third (or fourth) arm?
So the arm by itself isn't bad granting you the means to hold an extra item or a shield while two weapon fighting or fighting two handed.
However my question would be does it qualify you for multiweapon fighting -- and if it does do you now gain extra attacks from the third (or fourth) arm?
to me it clear that the arms themselves don't grant extra attacks just for having them.
However other abilities can grant additional attacks.
For example
ferral mutagen + 2 x vestigal arms + two weapon fighting
the ferral mutagen turns two of your 4 hands into claws, leaving you two other hands free for holding weapons.
because your allowed to mix natural with weapon attacks you get your normal attack routine in this case TWF and get all your natural attacks at -5
so say BAB of 6, improved TWF light wep offhand
+4/+4/-1/-1 wep attacks plus +1/+1/+1 bite claw claw
although you qualify for multi weapon fighting I don't believe the feat itself grants extra attacks. and vestigial arms are pretty clear about not granting attacks by themselves
maxed out
BAB 15, greater TWF, multiattack, haste
+13/+13/+13/+8/+8/+3/+3 weapons plus +11/+11/+11 bite claw claw
for a total of 10 attacks
take vivisectionist for sneak attack and you've got quite the little brawler. Master Chymist would also let you add +6 brutal dmg to all those attacks if using only simple/natural weapons
of course by RAW you can do this without vestigal claws and going claws on your feet instead of hands, but thats a bit cheese for me at least this way it costs 2 discoveries to do it.