A lot of the artwork from the many books over the years has depicted marines using large two handed weapons in combat at times. Is there any benefit to doing this? The rules as written seem to lean toward dual wielding as far as what makes you an acceptable melee combatant. Even the cover of The Emperor Protects depicts a marine with what looks to be a two handed sword.

Most two handed weapon inflict 2d10+X damage...

The Relic Blade in the corebook for example is two handed and a chain greatsword would do something akin to 1d10+12 R, Pen 6 (based on eviscerator).
I would believe more great weapon will appear in future installements

In the rules section I responded to a simular thread and offered a change of doubling StB when wielding 2h weapon when the two weapon wielding (melee) talent is purchessed. Since 2d10+stb does not = 1d10+StB+1d10+StB. Also would modify swift attacks for 2h weapon to be 2 attacks at +10WS bonus and lightning attacks to be 3 attacks at +20WS bonus, still giving duel wielding more attacks when off hand is factored in, but making 2h the better choice when facing large foes since per hit will do more damage and the better chance of hit.

There are 3 2handed power weapons in Rites of Battle

BrotherHostower said:

Nice, I am hesitant to buy that book since I was alittle disappointed with the section on chaplains, but it sounds like the other stuff is worth it once I can find it in a store and flip through it I will probably get it.

I was hoping for something actually from the rulebook, and not house rules. Is there actually a normal rule for this?

WillisRBC said:

Apparently in the Rites of Battle book, but not that I am aware of in the DW core. If want anwsers from the book, book best place to look. Ask in forum and get house-ruleings and speculation.

WillisRBC said:

There is nothing in the core book that states that wielding a weapon two handed in any way increases its damage. As was said earlier, any weapon that must be wielded in two hands already accounts for this increase in damage, and there is no benefit to wielding a one handed weapon in two hands. Also, there is no penalty to damage for dual wielding weapons.

Talk to your GM if you feel there ought to be, but really the system is solid as is, and no real reason to change it.

There's no benefit in doing so by RAW, but I suggested in another thread that it makes sense to make the Thunderhammer merely unbalanced when wielding it with two hands, so you can parry with it.

If you are thinking about a house rule, it's worth noting that using a weapon in two hands is not done for more power, it's done for more control of a weapon. Hence giving an increase is damage would be pretty ludicrous. I'd recommend either a parry or WS bonus, or perhaps a PEN bonus to represent the blows being much better placed.