Help me understand the Xill's numbers: Multiattack and Multiweapon Fighting...

[ksbsnowowl]

The Xill from the SRD is an outsider with four arms:

(click to show/hide)

Xill
Size/Type:    Medium Outsider (Extraplanar)
Hit Dice:    5d8+10 (32 hp)
Initiative:    +7
Speed:    40 ft. (8 squares)
Armor Class:    20 (+3 Dex, +7 natural), touch 13, flat-footed 17
Base Attack/Grapple:    +5/+7
Attack:    Short sword +7 melee (1d6+2/19-20) or claw +7 melee (1d4+2) or longbow +8 ranged (1d8/×3)
Full Attack:    2 short swords +5 melee (1d6+2/19-20, 1d6+1/19-20) and 2 claws +5 melee (1d4+1); or 4 claws +5 melee (1d4+2, 1d4+1); or 2 longbows +4 ranged (1d8/×3)
Space/Reach:    5 ft./5 ft.
Special Attacks:    Implant, improved grab, paralysis
Special Qualities:    Darkvision 60 ft., planewalk, spell resistance 21
Saves:    Fort +6, Ref +7, Will +5
Abilities:    Str 15, Dex 16, Con 15, Int 12, Wis 12, Cha 11
Skills:    Balance +13, Climb +10, Diplomacy +2, Escape Artist +11, Intimidate +8, Listen +9, Move Silently +11, Sense Motive +8, Spot +9, Tumble +11, Use Rope +3 (+5 with bindings)
Feats:    Improved Initiative, Multiattack^B, Multiweapon Fighting
Environment:    Ethereal Plane
Organization:    Solitary or gang (2-5)
Challenge Rating:    6
Treasure:    Standard
Alignment:    Always lawful evil
Advancement:    6-8 HD (Medium); 9-15 HD (Large)
Level Adjustment:    +4

The attack and full attack lines are... not adding up for me?

Attack:    Short sword +7 melee (1d6+2/19-20) or claw +7 melee (1d4+2) or longbow +8 ranged (1d8/×3)
Full Attack:    2 short swords +5 melee (1d6+2/19-20, 1d6+1/19-20) and 2 claws +5 melee (1d4+1); or 4 claws +5 melee (1d4+2, 1d4+1); or 2 longbows +4 ranged (1d8/×3)

He has Multiattack and Multiweapon Fighting, but I'm not seeing that they should interact in the way they appear to be doing in this monster's stats...

On the full attack he is Multiweapon Fighting (effectively TWFing) with two light weapons, so I see how the +7 attack bonus became two short sword attacks at +5 each.  What I'm not seeing is how his claw attacks are at +5; shouldn't they be at +3?  Attack at +7 for a single claw, -2 for secondary natural weapon (thanks to multiattack), and shouldn't there also be a -2 applied to these attacks because he is two-weapon-fighting (multiweapon fighting, whatever)?

And if he merely attacks with 4 claws, why is it at +5?  If he attacks with one claw, it is at +7, indicating it is a primary attack.  As such, shouldn't all four claws be at +7?
Edit: the fact that they give two damage values for the four claw attacks shows me that they are still treating one claw as a primary weapon, and all other claws as secondary weapons.  This is ... wrong, isn't it?

Also, how is attacking with two short swords +5 (using his +2 Str mod), and attacking with two longbows is only +4 (using his +3 Dex mod)?  I can see taking a -2 for TWF, which should put it at +6, not +4...

[phaedrusxy]

For everything else, yeah they almost certainly screwed up. D&D examples are notorious for doing that.

For the longbows, they are not light weapons. So he takes a -4 to his attacks, even with TWF/MWF.

[ksbsnowowl]

Ah yes.  See how often I have things use TWF?

[Garryl]

TWF (and MWF) penalties apply only to manufactured weapons, not natural weapons. The +5 attack bonus for the claws in shortsword/claw is correct.

With the 4x claw routine, one of the claws (possibly two if they are considered paired weapons, as claws commonly are) should be considered primary, and thus do the full damage and have a +7 attack bonus, not +5. The others are indeed secondary, and thus deal reduced damage and only have a +5 attack bonus.

Phaedrus covered the longbow thing.

[ksbsnowowl]

Cool.  Okay, it's starting to make sense now.

-4 TWF for longbows, because they aren't light.

TWF penalties to swords only, not natural secondary weapons.

Two claws primary, two claws secondary. -> this part actually is incorrect in the stat block.  Should be:
2 Claws +7 (1d4+2) and 2 Claws +5 (1d4+1).

Even treating the claws as pairs of primary and secondary, it's just odd, because comparing it to the other four-clawed creature in core (the Girallon), its 4 claws are all primary.

[Garryl]

/shrug

When a creature has more than one natural weapon, one of them (or sometimes a pair or set of them) is the primary weapon. All the creature’s remaining natural weapons are secondary.

Having more than just two natural weapons be primary is okay, so the Girallon is fine in that regard. But we know that Xill have at least one secondary claw, and it makes more sense for them to have 1 primary/3 secondary or 2/2 than to have 3/1. Plus, Xill are more closely related to humanoids (and thus not ambidextrous), as opposed to Girallons being related to (magical) beasts, and thus operating under a different paradigm.

[RedWarlock]

Two claws primary, two claws secondary. -> this part actually is incorrect in the stat block.  Should be:
2 Claws +7 (1d4+2) and 2 Claws +5 (1d4+1).

Even treating the claws as pairs of primary and secondary, it's just odd, because comparing it to the other four-clawed creature in core (the Girallon), its 4 claws are all primary.

No, I think the claws are all primary, even with 4. They're only split when using manufactured weapons in half of them. Without those swords, they're all one set of primary attacks.

[ksbsnowowl]

I also feel that's how it should be, but the stat block is treating them all as secondary attacks (for attack bonus), or splitting them between primary or secondary (for damage).

I can see an argument for going two primary, two secondary, but also know this contradicts most examples in the various monster manuals.

[RedWarlock]

The stat block is definitely borked. (I mean, a comma in the 4 claws damage parentheses? WTF? Which goes where?)

I'm just saying how it should be. The claws should be all primary attack bonus, and all full strength.

[ksbsnowowl]

For additional comparison, here are the attack lines of the Arrrow Demon from MM3:

Attack: 2 Large +1 composite longbows (+5 Str bonus) +14/+14 ranged (2d6+6/×3) or claw +15 melee (1d6+5)
Full Attack: 2 Large +1 composite longbows (+5 Str bonus) +14/+14/+9/+9 ranged (2d6+6/×3) or 4 claws +15 melee (1d6+5)

Like the Xill, the Arrow Demon is a humanoid-shaped outsider with four arms and four claw attacks.  All four claw attacks are treated as primary.