Mithral Weapons?

[McNinja]

Since mithral is substantially lighter than iron or steel and removes some of the negatives of the heavier armors, could a mithral weapon remove some of the negatives of non-light weapons, mainly the fact that they're not light or finesse?

A mithral longsword could gain the "light" weapon property.
A mithral greatsword could lose the "heavy" weapon property and possibly become one-handed, assuming mithral halves the weight.

Right now this is all hypothetical... but I think it would be hilarious for a fighter to be dual-wielding mithral greataxes.

[Randomthom]

Some weapons also rely on their weight to be effective. particularly the large bludgeoning ones like mauls, maces and, to a lesser extent, slashing weapons like axes, halberds, longswords & shortswords.

[Joe the Rat]

Over in "Tales from my D&D Campaign" (YouTube. Look it up.) the party cleric eventually acquires a mithral mace. Because it's a lighter metal, it is significantly larger to maintain the "bashin' weight". In other words, Mithral lets you make comically oversized weapons.

(the DM also rules mithral as counting as silver for DR purposes, because otherwise what's the point of mithral weapons?)

[Logosloki]

In 3.5 and in PF, a mithral weapon merely weighs half as much. This does not change the weapon's size category or the ease of which the weapon is wielded.

[Phawksin]

If you instituted a rule that mithral removed the Heavy quality it would have some really interesting (and totally believable) ramifications. GWF wouldn't work with those weapons but small PC's could use them without penalty. Technically speaking its not a power boost and I would be all about it. If you gave the Light quality to weapons that don't already have the Heavy quality it would be a small boost, basically granting access to the dual wielder feat without needing the feat, so that's problematic I think. If it gave the Finesse quality that would be a strict power increase to every dex build, specifically Rogues (and maybe Monks depending on how lenient your DM is). That's likely fine for a magic item on its own, but is too powerful for just mithral.

[EvanescentHero]

That's likely fine for a magic item on its own, but is too powerful for just mithral.

Except mithral armor is included with the magic items, so it's considered the same category. I don't see an issue.

[Blood of Gaea]

Right now this is all hypothetical... but I think it would be hilarious for a fighter to be dual-wielding mithral greataxes.

Better yet, sneak attack with a Lance from horseback.

[Mr.Moron]

Some weapons also rely on their weight to be effective. particularly the large bludgeoning ones like mauls, maces and, to a lesser extent, slashing weapons like axes, halberds, longswords & shortswords.

As pseudo-magical material, why can't it just be lighter while still delivering the same force upon impact?

[Phawksin]

Except mithral armor is included with the magic items, so it's considered the same category. I don't see an issue.

Totally. What I mean to have said was it should be a magic item with a higher rarity than uncommon like mithral armor. Actually, the Sun Blade is a long sword with the finesse property and is rare, so mithral weapons as rare or very rare magic items with the finesse property would actually be pretty sweet.

[EvanescentHero]

Totally. What I mean to have said was it should be a magic item with a higher rarity than uncommon like mithral armor. Actually, the Sun Blade is a long sword with the finesse property and is rare, so mithral weapons as rare or very rare magic items with the finesse property would actually be pretty sweet.

Ah, all right, fair enough. I agree that adding either light or finesse, or removing heavy so small characters can use them, would be the way to go for mithral!

[Safety Sword]

Ah, all right, fair enough. I agree that adding either light or finesse, or removing heavy so small characters can use them, would be the way to go for mithral!

As posted above you should also consider making them count as silver (or perhaps magical) for the purposes of overcoming resistances.

It could be the perfect "magical" weapon for people worried about all those +X's screwing things up.

I think 5E is liberating for DMs in this regard. I can make a weapon with special properties without it having fixed bonuses to attack and damage.

[EvanescentHero]

As posted above you should also consider making them count as silver (or perhaps magical) for the purposes of overcoming resistances.

Oh, of course. Adamantine should likely do the same thing, though I'm not positive what else adamantine weapons would do.

[McNinja]

Oh, of course. Adamantine should likely do the same thing, though I'm not positive what else adamantine weapons would do.
They could potentially lightsaber through iron doors or something like that.

[Coidzor]

They could potentially lightsaber through iron doors or something like that.

If you wanted to bring back sundering in a big way, you could have common materials have vulnerability to damage from adamantine weapons, I suppose.

[Safety Sword]

If you wanted to bring back sundering in a big way, you could have common materials have vulnerability to damage from adamantine weapons, I suppose.

Don't forget Ironwood for the druids.

Of course the beauty of all these things is that you can make your own process for their manufacture. So, it's possible that these "pseudo-magical" materials are actually magically produced... which just makes them magical materials.

Needing to journey to the sacred Ironwood grove where the trees themselves teach you the secrets of working Ironwood staves. Now that sounds like something a druid might like to get involved with!

[Blood of Gaea]

If you wanted to bring back sundering in a big way, you could have common materials have vulnerability to damage from adamantine weapons, I suppose.

Just call it a "Siege Weapon" which does double damage to objects and structures. Just modified wording of "Siege Monster" from the MM.

[Mr.Moron]

Oh, of course. Adamantine should likely do the same thing, though I'm not positive what else adamantine weapons would do.

When used to attack constructs made of stone/metal, earth elementals and other creatures of rocky composition they have vulnerability to that attack.

[Knaight]

Since mithral is substantially lighter than iron or steel and removes some of the negatives of the heavier armors, could a mithral weapon remove some of the negatives of non-light weapons, mainly the fact that they're not light or finesse?

A mithral longsword could gain the "light" weapon property.
A mithral greatsword could lose the "heavy" weapon property and possibly become one-handed, assuming mithral halves the weight.

You could do this, but honestly a lot of what makes weapons behave the way they do is more geometry than materials. Take a greatsword, halve the weight, and it still handles very differently due to being quite long. That's not to say that there wouldn't be any advantage, or that there would be no changes to how people fight, but something like making a great sword one handed seems off to me. A +1 bonus even if non magical wouldn't be unreasonable. Armor gets a lot more mileage out of being mythril.

Then you stick the other things on. Mythril doesn't necessarily rust or tarnish, for primarily stabbing weapons it's largely just better, to some extent it can be used to protect wooden parts better than steel (and thus resist breaking attempts), etc.