Number one, what are the benefits to dual wielding vs. lightning attack? As far as I can tell lightning attack gives you more attacks, and doesn't stack with the dual wielding talents, correct me if I'm wrong.

Also, what upgrades would you be able to put on a force sword?

Can one have two wrist mounted weapons, while also dual wielding?

How exactly do opposed tests work? The mechanic doesn't make too much sense to me, i.e. how degrees of success work with that kind of check.

Finally, can you still use biomantic powers if you have cybernetic arms and whatnot?

Thank you in advance.

Dual Wielding with multiattacks is elaborated upon in the errata. No clue where to get it, sorry. In short, it states that if you're dual wielding and use lightning attack you get 3 attacks with 1 weapon and 1 attack with the other weapon. The same applies with swift attack, except 2 and 1 attack(s).

You can also use lightning attack with a pistol in the "off-hand' (I'd hope you're ambidextrous at this point) and get 3 attacks with the melee and 1 with the pistol. In this case you'd need Dual Wielding (Ballistic) AND (Melee).

No idea. Melee weapons are pretty restricted in their upgrades in general. I think there's Lathe and Mono (but mono only works for primitive weapons). Also, by Force do you mean Power Sword?

I'd vote yes, but you can only operate so many weapon in one round. Certainly be nice to have the versatility if you happen to be made of money. Note, I don't think flamers can be mounted on wrists, but that might be Macharian's work, not official stuff.

Okay, for opposed checks:

Both parties roll. Often, one party is considered an "aggressor" of sorts. For example, disarm is an opposed WS check, with the disarmer being the aggressor. If both parties fail their checks, the aggressor's action fails. If the aggressor fails his check and the defender succeeds his check, well, then clearly the aggressor's action fails. Now for the tricky bit: If both parties succeed, and the aggressor succeeds by more degrees of success than the defender, then the aggressor's action succeeds.

e.g. Strin is trying to disarm a cultist. They both have swords. Strin's WS: 40 and the cultist's WS: 50.

(Strin's roll (Success(degrees)/Fail)) (Cultist's roll (Success(degrees)/Fail)) (The outcome)

(30 S1) (30 S2) (The disarm fails.)

(62 F) (75 F) (The disarm fails.)

(15 S2) (30 S1) (The disarm succeeds.)

(38 S0) (52 F) (The disarm succeeds.)

(8 S3) (42 S0) (The disarm succeeds and Strin recovers his opponent's weapon (assuming he has a free hand))

Man, I don't even know what biomantics are.

Thank you that cleared alot of stuff up.

But, what book are lathe weapons on?

Force weapons are not power weapons, inquisitors handbook.

And biomancy is a psyker discipline.

Inquisitor's HB, page 147 for Lathe blade.

I assume a force sword could receive similar upgrades as a normal sword.

Mono is an upgrade taken for any melee weapon with the primitive trait usually - representing a mundane metal weapon being made super sharp, or having pneumatic pistons on hammers etc.

Lathe-blade upgrade is a bit trickier as i think it has to be any kind of bladed weapon - representing super dense metals and advanced alloy techniques used by the Lathes forgeworlds.

Both of these upgrades can be taken on power weapons but you ONLY benefit from them while the power field is turned off... as there is nothing in the rules to cover turning off the power field, i think it's safe to say you'd lose ALL pen on the weapon and possibly some points of damage too, so the upgrades can help negate this loss.

Another upgrade to look into is the Storm upgrade for power weapons found in black crusade (unsure if it's in any other books) - this represents a basically supercharged power field that increases damage and pen, but carries a chance of accidentally damaging yourself with the power field.

There's also toxin and wrist mounted upgrades in various books and if your GM is okay with it you could use suspensor bolts on a 2-handed melee weapon to allow it to be used 1-handed with only slight reduction to damage.