D&D 5E Oversized and undersized weapons in 5e

[Li Shenron]

I haven't had time to check from my trip to the FLGS, do the MM monsters sometimes have oversized or undersized weapons?

Or do they just use the same weapons as the characters, just picking the ones of appropriate size (e.g giant using greatswords or greataxes, tiny creatures using only daggers etc.)?

I was thinking whether we need any rules for over/undersized weapons at all in 5e.

I don't like to be restricted, so I would definitely like to occasionally see giants with giant-sized daggers or rock-throwing slings and pixies with pixie-sized longbows and crossbows, but also giants with giant-sized greatswords and bows shooting arrows the size of a ballista, and pixie with diminutive daggers and slings.

Often there really is a suitable weapon already (e.g. a human shortsword is a pixie's greatsword, a human greatsword is a giant's dagger etc.), or re-skinning is enough. But for those other cases, would you scale the damage or would you just go with the same damage as the medium-size weapon? For instance, would you use the normal dagger damage for a pixie wielding a pixie-sized dagger, or would you use a smaller damage? Conversely, would you use the normal greatsword damage for a giant wielding a giant-sized greatsword, or would you use a larger damage?

[note: keep in mind that the pixie already has a low Strength and the giant already has a high Strength, so the total damage is already different from that of a human wielding similar human-sized weapons]

 

[Paraxis]

The general guideline is tiny weapons mostly do just 1 point of damage, some tiny creatures do 1d4 with natural attacks like a bite, if the attack is listed as claws plural that can be 2d4 instead. For bigger creatures each size category just adds a die of damage to the weapon, so a huge greatsword is 6d6.

The above is not 100% some things seems to differ a bit.

Small creatures like halflings, gnomes, and goblins just use normal human sized weapons but if the weapon has the keyword "heavy" they have disadvantage on attacks with it.

The spell enlarge does not make your weapon do an extra complete die of damage it just adds 1d4 to your damage. So an ogre using a longsword does 2d8 base damage, a human enlarged to ogre size with a longsword does 1d8+1d4.

Also note that most tiny monsters even if they only do 1 or 1d4 base damage have modifiers like extra poison damage or special conditions to make those natural attacks effective.

 

[Scorpio616]

Conversely, would you use the normal greatsword damage for a giant wielding a giant-sized greatsword, or would you use a larger damage?

[note: keep in mind that ... the giant already has a high Strength, so the total damage is already different from that of a human wielding similar human-sized weapons]

It's pretty simple for the 5E giants. You triple the damage dice for thier weapons since they are all huge.

True Giants are back at their 2E AD&D sizes and hitting like... well, giants.

 

[Li Shenron]

Are these rules laid out in the PHB/Basic, or did you reverse-engineer them from MM entries?

 

[Paraxis]

Are these rules laid out in the PHB/Basic, or did you reverse-engineer them from MM entries?

Not laid out exactly, the small creature thing and enlarge spell effects yes. The monster large size weapon thing is just how every instance in the MM is handled.

I do believe it was talked about in a tweet or article at some point, and I am sure it will be covered in the DMG come December.

 

[EugeneCarter1970]

For those that think the weapon's size doesn't impact the weapon's damage, a human could wield a sprite's tiny longsword and deal 1d8 damage instead of 1 damage. Alternately, I propose that the weapon's size does matter (DMG p277), and despite the Enlarge/Reduce says that it deals an extra 1d4 damage, I don't believe that this extra damage overrides the inherent damage increase from a weapon that was increased. All enlarge methods should have the same base features: squares occupied for fighting, weapon damage dealt, etc. If you wildshape into a giant ape and wield a huge great axe, deal 3d12. If you Wish to be large and wield a large longsword, deal 2d8 onehanded.
Extra effects can come from a variety of other ways that you can be large, such as the 2nd level spell boosting the damage by 1d4 per attack, or the Giant's might ability to boost one attacks damage by 1d6, but these are extra effects and not the same effect that being large entails. The system should work no matter how you get to the same situation; if a person is enlarged and picks up a large weapon, or a person is large and picks up an enlarged weapon, or a person is enlarged with their weapon.

 

[Tonguez]

I’d leave as is- a giant using a great sword gets normal great sword damage + giant strength.

I would allow for gigantic swords though that do Up to *3 damage and knockdown and require Str18 to weild

A pixie does 1 pt of damage with a pin, but with a dagger gets 1d4

 

[Kobold Stew]

I think the rules are mostly clear, just not what people want.

• A Medium character Enlarged does +1d4 damage, not double damage (PHB, confirmed by Sage Advice more than once).
• A Medium character using an ogre's weapon does double damage (or whatever the creature's statblock says, taking strength adjustments into account), but attacks with disadvantage. (Up to the DM whether someone can use a weapon sized more than 2x sizes larger).
• A Medium character Enlarged who then picks up an ogre's weapon does double damage (or whatever the creature's statblock says), no disadvantage (assuming the character has proficiency).

(Up for interpretation: With Enlarge, an item "dropped" by an affected creature returns to its normal size "at once". Does this count for ranged weapons, i.e. an enlarged arrow becoming Medium again once fired? Most would say no [it's shot, not dropped], but I can see the case for yes [ithe object leaves the area affected by the spell].)

(Also up for interpretation: whether one can benefit from GWM when using an oversized weapon. Using an oversized weapon gives disadvantage; GWM requires proficiency with the weapon to benefit from -5/+10. So is the disadvantage from using an oversized weapon due to not having proficiency? Arguably, yes (and if so, then also arguably one could take the Weapon Master feat to train in four oversize weapons. Finally a use for that feat). EDIT: guess this isn't up for interpretation! Thanks, @fluffybunbunkittens

 

[fluffybunbunkittens]

So is the disadvantage from using an oversized weapon due to not having proficiency?

There is no disadvantage for not having weapon proficiency. You just don't get your proficiency bonus.

On the bigger topic, Enlarge-like effects typically already give a damage boost to account for size-related things. I'd just say you don't get to double-dip.

 

[fluffybunbunkittens]

(Wait, this thread was revived from 10 years ago?)

Anyway, exact rules from DMG (under monster creation):

Big monsters typically wield oversized weapons that deal extra dice of damage on a hit. Double the weapon dice if the creature is Large, triple the weapon dice if it's Huge, and quadruple the weapon dice if it's Gargantuan. For example, a Huge giant wielding an appropriately sized greataxe deals 3d12 slashing damage (plus its Strength bonus), instead of the normal 1d12. A creature has disadvantage on attack rolls with a weapon that is sized for a larger attacker. You can rule that a weapon sized for an attacker two or more sizes larger is too big for the creature to use at all.

We could just say they don't apply to the PCs, if not for the cursive bit tacked on at the end.