I'll just have to describe this one

[Sloanzilla]

1. Party's dwarven fighter is dominated and has orders to "kill the paladin"- the non dominated members of the party know he is dominated and he's standing next to the non dominated cleric. The dwarf has a warhammer and a heavy shield out.

2. The cleric has a light shield and a weapon and has been mostly casting each round. We've always ruled that with a light shield you can shift your weapon into that hand and cast with the other. We've never really had to figure out if- the second after you cast- you shift the weapon back into your casting hand.

3. Dwarf decides that he wants to sheath his weapon, use quick draw to pull out a net and throw it at the paladin.

4. Cleric decides he wants to AOO the dwarf by attempting to initiate a grapple. (which would happen a second before the net throwing, right?)

5. Dwarf decides he wants to AOO the cleric with a regular attack.

So here's my mess.
1. The dwarf has sheathed his weapon and pulled out a net. So he no longer threatens, right? He has no shield bashing feats and does not have a spiked shield, so I wasn't sure if his shield- which he has only ever used for defense- would still give him an AOO.
2. The cleric either A. is holding a shield and weapon in one hand and nothing in the other or B. is holding a light shield in one hand and a weapon in the other. If A. I'd rule he could attempt a grapple with his one free hand, but does not threaten because he has no threatening weapon readied, so no AOO. If B. (He shifted his weapon back into his hand after casting)he has no hands free to grapple, right? Or could he drop his weapon as a free action within the AOO and then attempt a one handed grapple?

Anyhow, I just winged it and everyone disagreed with various rulings.

Ugh. One of my many questions above there is whether casters shift weapons BACK to their primary hands after shifting away to cast.

[Michael Sayre]

Grappling is actually a standard action and I'm not aware of you even being able to grapple as an AoO without some investment of feat or ability (if at all). So the situation is kind of moot. Unless you have a house rule that allows grappling in place of attacks of opportunity, it seems like neither of them could have done anything here. The cleric can drop his mace as a free action and then initiate a grapple with a -4 penalty since he's only got one free hand, but that's a little separate from the fact that I don't belive this works in the first place. Grapple isn't like Trip, where it can be made in place of one of your normal attacks, it is its own separate standard action.

[Sloanzilla]

ok cool, I googled "can you grapple as an AOO" and all I found were people saying you could, but I prefer your ruling due to logic.

[Alexander Kilcoyne]

You can't grapple as an AOO- you could only make CMB's that are specifically called out as "can be in place of a melee attack". look at the difference between Trip/Disarm and Grapple.

[MyTThor]

1) The dwarf could always take an AOO with an unarmed, although I'd assume he doesn't have IUS so he'd actually provoke for that. There's nothing to say he couldn't use the shieldbash for it, but here's how I'd handle it.

"He's going to attempt to grapple you, which will provoke. At this point you don't have a weapon ready."

If the player says "what about my shield?" Then great, he gets to shieldbash him. But as you said, he doesn't generally think of his shield as a weapon, and you're under no requirement to remind him of the possibility. The most realistic thing would be to see if he thinks of it, since it's out of the box for his character.

2) Switching a weapon from hand to hand is no sort of action, so RAW there's no delay it can take. I'd rule that the only time when the weapon wouldn't be useful would be while the character's casting (say he provokes by casting, and someone takes an AOO against him with unarmed, provoking. He couldn't take that AOO with his weapon. But once the round is over, he's got it back in his hand.

Other points:

1)If the Dwarf was dominated to kill a Paladin, why would he drop a lethal weapon and pull out a net?

2) Note that James Jacobs has said to prevent this confusion he'd rule (unofficially) that you can just cast with the hand the Light Shield is strapped to.

3) As stated above by others, grapple is not one of the combat maneuvers you can do as an AOO.

[Sloanzilla]

I let dominated people do what they want, provided it is within reason of their instruction. The dwarf has typically found netting people and then hammering on them to be a fairly good way to kill things, so I felt like "keep 'em from moving, then kill 'em" would have been a fair interpretation of his goal. Note that I'd originally ruled your way (You just want to hit him with your hammer) but the player gave what I felt was a decent argument to try the netting.

No grapple as an AOO solves a lot of problems, as does #2 (ruling that you can just cast with the light shield hand to avoid too much weapon shifting). Thanks again.