What's a reasonable ruleset for an "invisible weapon?"

[Frogwarrior]

I'm homebrewing (5e) a magic item that is a rapier with a permanent Invisibility effect (only the sword is invisible, not the wielder), and trying to think how that should affect the rules.

The most obvious idea is to deny any DEX bonus to AC, but I think it would be odd that you can't learn to read the movements of the swordsman.

I'm toying with, "you only get AC from armor, not DEX or shield, until you pass an INT check" but that would take a bunch of rolling.


I'm creating this for a boss character who is an evil mime.... bard (swords) / rogue (assassin). Can give bardic inspiration through mime dancing instead of speaking. Cannot speak, as the sword also is under the effect of a permanent "silence" spell. Also, he has no tongue. This mime is one of several evil clowns, all bard multiclasses (bard/sorceror, bard/warlock, bard/oathbreaker paladin).

[Man_Over_Game]

To simplify things, I'd probably just limit it to just using stats and rolls from the attacker.

Straight Advantage per attack is probably what best models this, but that's obviously too strong.

Why not make it something like "Your attack rolls with this weapon is considered to be no less than your Sleight of Hand bonus when attacking creatures that cannot see the blade". This would mean that a maxed-out character could never roll less than a 17 to hit, but...it's an invisible sword.

[Frogwarrior]

Interesting... I hadn't considered Sleight Of Hand. But how powerful would you need to be for that to be meaningful? Even with Proficiency 5 and 18 Dex, that's still only a 9.

I don't want the invisbility to be too powerful, since the wielder will still have to make obvious lunging and thrusting movements to get any meaningful use out of it, which could in theory be accounted for by an intelligent opponent... I'm leaning towards "the target of the attack makes in INT roll, or they do not get DEX or shield bonuses."

Advantage is DEFINITELY too strong.... especially since it will start in the hands of a character with rogue levels, and advantage always allows sneak attack.

[heavyfuel]

Interesting... I hadn't considered Sleight Of Hand. But how powerful would you need to be for that to be meaningful? Even with Proficiency 5 and 18 Dex, that's still only a 9.

Expertise can double your prof bonus

[Frogwarrior]

Expertise can double your prof bonus

Thanks! I'm pretty new to 5e.

[Dienekes]

A bit extrapolated, but how about “attacks made with this weapon can’t trigger Reactions.”

The armor and shield are still there. And the enemy can still see your hand moving so can dodge. But they’re going to find it difficult to actively parry with Parry maneuver, or successfully block with the Shield spell. And it’s pretty simple and requires no additional rolling.

[Unavenger]

Against a reasonably competent opponent, your invisible sword should be surprisingly useless, I would think - it's possible to extrapolate the position of the sword entirely from how it's being held, and so long as your opponent has a moment to get to grips with how long or short your weapon is, they should be reasonably able to block it. I would call it an interesting way to accidentally mislay your +2 rapier and call it a day.

[Man_Over_Game]

A bit extrapolated, but how about “attacks made with this weapon can’t trigger Reactions.”

The armor and shield are still there. And the enemy can still see your hand moving so can dodge. But they’re going to find it difficult to actively parry with Parry maneuver, or successfully block with the Shield spell. And it’s pretty simple and requires no additional rolling.

It's a little bit too niche. I'd also make it so that being hit strips you of your Reaction as well. As-is, there are very few Reaction effects that'd trigger off of an attack. Heck, Reactions as a whole are very niche to utilize, but removing them entirely from your opponent's strategy is still a pretty good effect.

Thanks! I'm pretty new to 5e.

That, and proficiency bonuses go up to +6. So you can have +6 +6 + 5 total.

[Yakk]

Invisible Rapier

The first time on your turn when you attack a creature who cannot see invisible objects, you have advantage.

The idea is that your 2nd and later hit, you've telegraphed yourself a bit.

This also makes it a great weapon for a rogue, and not as good for a fighter type.

[Frogwarrior]

Against a reasonably competent opponent, your invisible sword should be surprisingly useless, I would think - it's possible to extrapolate the position of the sword entirely from how it's being held, and so long as your opponent has a moment to get to grips with how long or short your weapon is, they should be reasonably able to block it. I would call it an interesting way to accidentally mislay your +2 rapier and call it a day.

I was thinking the same thing; that's why I'm thinking the target can avoid whatever the penalty is by passing an Intelligence check. (And after passing it once, it never needs to be passed again.) So against the PCs, it will be really annoying the first time they fight it, after which it becomes useless - but, after obtaining it as a boss drop, it will always be usable by the PCs.

Invisible Rapier

The first time on your turn when you attack a creature who cannot see invisible objects, you have advantage.

Advantage seems TOO powerful for rogues, since that's nearly a guaranteed sneak attack every round.



Here's my current draft:

Attuning to it means you can see it as from a see invisibility spell.

Every non-willful defensive effect (armor, Ring of Protection, etc) is as normal. Willful effects like DEX and shield bonus to AC, damage reduction from Parry, etc, are all halved. The target of the effect can make an INT check (or should it be WIS?) to avoid this; avoiding it makes them permanently immune.

Subtle Attack: Even if the target has made the check, the can still attempt to use Sleight of Hand (opposed to Perception) to get the same bonus, but the Subtle Attack gets no STR/DEX bonus to damage.



... But in that form, it could unnecessarily multiply dice rolls. Just being able to completely surprise anybody in broad daylight because they don't know your weapon is drawn, is a bonus already.

[Tvtyrant]

Advantage on the first attack they make in combat would be my suggestion. That's potent but not broken, and fits with "secret weapon" idea.

[Frogwarrior]

Advantage on the first attack they make in combat would be my suggestion. That's potent but not broken, and fits with "secret weapon" idea.

That... is so VERY much simpler haha.

I'd probably add something like "it only works against you if you've never seen it before" and "if it's a surprise attack from behind you haven't seen it before, and the next attack will still get advantage."

So my assassin rogue / whispers bard mime will try to get a surprise sneak attack critical, and still get a free sneak attack on round 1 no matter the initiative roll.

[Yakk]

Advantage seems TOO powerful for rogues, since that's nearly a guaranteed sneak attack every round.

Rogues already almost guarantee sneak attack every round. They just need 1 ally adjacent to the target.

Using your weapon and an attunement slot for this isn't that far off a good T2 or a T3 item.

Are your melee rogues really having a problem getting sneak attack on a target?

Let's look at what it does.

You are a level 11 Rogue with 6d6 sneak attack using a +2 rapier. Elf with elven accuracy while we are at it. You use booming blade (either via feat, or an AT).

There is an ally adjacent to your target. Your accuracy is +11 to hit.

The enemy has 16 AC.

Your attack deals 3d8+6d6+7 damage.

You hit on a 5+ crit on a 20, so 17/20 dice and 16/20 static damage for 29.325 + 5.6 = 34.925 damage per round.

You now get this rapier. You are down an attunement slot. Your accuracy is now +9 to hit, but you have trip-vantage.

It deals 3d8+6d6+5 damage at 97% accuracy and 14% crit chance. 1.11 dice multiplier, .97 static damage, for 38.295 + 4.85 = 43.145 damage per round.

A 24% DPR boost.

Next to you is a Fighter using a Flametongue Greatsword for 15.33 dice damage and 5 static damage. Without advantage, they have a 2.25 dice multiplier and 2.1 static damage multiplier for 44.925 DPR.

If they are a champion, +2.3 DPR (.15 extra crits/action).

With GWM, have 15.333 dice and 15 static at 1.65 dice mult/1.5 static for 47.8 DPR.

BM burning dice on misses gets 30.3 from miss-by-1, 27.3 miss-by-2, 24.3 miss-by-3, 21.2 miss-by-4 (average of 25.8). They get 0.6 of these/round for an extra +15.4 DPR (up to 8 actions per short rest doing this). Action surge for another 47.8 damage on that round.

So a Rogue with a rapier that gives auto-advantage, using booming blade, still pales next to a fighter using a rare attunement weapon.

Conclusion: A rare attunement invisible rapier that grants advantage on your first attack on your turn is decent, but doesn't break anything. In the hands of a Rogue, it is about as good as a Flametongue greatsword in the hands of a fighter.

[Fitz10019]

When an invisible person picks something up, that item becomes invisible. However, grappling with an invisible person does not make one invisible.

For the invisible rapier, the first successful attack 'bloodies' the blade, making it less-than-invisible. It's ideal for betrayals, but not dominant in a longer engagement. Now just figure out what action 'cleans' the blade back to being really invisible.

[Frogwarrior]

Rogues already almost guarantee sneak attack every round. They just need 1 ally adjacent to the target.

... You raise some good points. Shows my inexperience, really.

When an invisible person picks something up, that item becomes invisible. However, grappling with an invisible person does not make one invisible.

For the invisible rapier, the first successful attack 'bloodies' the blade, making it less-than-invisible. It's ideal for betrayals, but not dominant in a longer engagement. Now just figure out what action 'cleans' the blade back to being really invisible.

I could see a floating bloodstain being easier to dodge or parry. Maybe it takes an action to clean the blade with a cloth.


So it's looking like the invisible blade itself isn't a huge advantage - I'm fine with that. Still the perfect weapon for a mime. I'm also planning on giving it some kind of turn on / off Silence effect, which will probably end up being deadlier. (Since, if the mime has closed with you for the assassination, you cannot call for help or cast spells with a verbal component.)

[Stattick]

Invisible Rapier, Rare, Attunement

This Rapier is invisible. It grants the wielder advantage on attacks made with it. Advantage is negated for this combat if the person being attacked makes an Intelligence Saving Throw (DC 15). This Save can be attempted every round at the end of the target's turn. If the target, or anyone else observing the rapier in action spends an action studying how the wielder is fighting with the invisible weapon, they can make an Intelligence (Investigation) check against a DC 15. If successful, the wielder does not get Advantage for attacking with the rapier.

The Rapier is considered magical for the sake of overcoming Resistance and Immunity.

[Frogwarrior]

Invisible Rapier, Rare, Attunement

This Rapier is invisible. It grants the wielder advantage on attacks made with it. Advantage is negated for this combat if the person being attacked makes an Intelligence Saving Throw (DC 15). This Save can be attempted every round at the end of the target's turn. If the target, or anyone else observing the rapier in action spends an action studying how the wielder is fighting with the invisible weapon, they can make an Intelligence (Investigation) check against a DC 15. If successful, the wielder does not get Advantage for attacking with the rapier.

The Rapier is considered magical for the sake of overcoming Resistance and Immunity.

I hadn't thought of allowing an action to overcome it, but that's not a bad idea. Not sure if a 15 DC is too high but I'll think about it.

Attunement makes it visible to you; if you are not attuned yet, all your attacks with it get disadvantage.

[Fitz10019]

Intelligence Saving Throw (DC 15)

+BAB, maybe? A fighter should get a handle on the situation sooner than a mage does.
That makes DC 15 more reasonable, perhaps.

[Yakk]

Invisible Rapier, Rare, Attunement

This Rapier is invisible. It grants the wielder advantage on attacks made with it. Advantage is negated for this combat if the person being attacked makes an Intelligence Saving Throw (DC 15). This Save can be attempted every round at the end of the target's turn. If the target, or anyone else observing the rapier in action spends an action studying how the wielder is fighting with the invisible weapon, they can make an Intelligence (Investigation) check against a DC 15. If successful, the wielder does not get Advantage for attacking with the rapier.

The Rapier is considered magical for the sake of overcoming Resistance and Immunity.

A saving throw every attack sucks, mechanically.

[heavyfuel]

I quite like the idea of the saving throw, although I wonder if Int should be it. Noticing stuff is generally tied to Wisdom. It's likely that even a dumb animal will figure out sooner rather than later that human without pointy stick hurts similar to human with pointy stick.

Although I would change the save DC to be Dex based instead of fixed 15. DC = 8 + wielder prof bonus + wilder dex bonus

+BAB, maybe?

Wrong edition, buddy

[BigDumbYak]

I think the group is really on to something with either the advantage on first attack or the sleigh of hand. Here's my take:

The first attack made by this weapon gains advantage.
When attacking with this weapon, the character may add their Sleight of Hand bonus to the damage of the attack.

I'm thinking damage boon, mainly cause:

1. you're already adding your dex + prof to the to hit, so its only ever going to be better if you specifically have expertise in Sleight of Hand.
2. If your foe fails to parry the blade, pretty good chance they are going to get stuck something fierce. Its not going to be some glancing blow, the foe has been outright bamboozled by your sneaky moves letting you score a viscous hit. So potential +11 damage at higher levels which could get up to +17 with expertise.

[Breccia]

The most obvious idea is to deny any DEX bonus to AC, but I think it would be odd that you can't learn to read the movements of the swordsman.

Your instincts are sound. No trained combatant would see someone moving as if they were holding a sword, in a magical world, and suspect nothing. Well, maybe if a child did it.

The most obvious advantage of an invisible weapon, to me, is "you walk right past guards as if you're unarmed". Depending on the circumstance, that could be more than enough.

If I were required to give it a combat advantage, I'd hesitate because "Feint" no longer exists. But I'd basically go with that. For the first attack of the combat, the attacker would be allowed a Free Action Deception check opposed by the target's Insight. If the check succeeds, that first attack has Advantage -- same as an unseen attacker or the Feinting Attack maneuver.

I would also throw on other restrictions such as "insect-level dumb targets are immune" and of course "If someone yells 'HEY that dude has an invisible rapier!' it won't work" but not tell them.

Honestly, being armed while appearing to be unarmed is between a moderate and major advantage. I'm not sure I'd really need to add to that. Hell, in a previous campaign I made a magic scabbard that made the sheathed weapon (and itself) invisible, and players really liked that.