Benefits of an invisible sword?

[Oryan77]

If a fighter wielded an invisible sword that only he could see, what type of benefits would he get vs an opponent?

 

[Dandu]

Invisible creatures have +2 to attack. Since only the sword is invisible in this case, perhaps just a +1 to attack would be appropriate.

 

[shadyizok]

I don't think it is mentioned anywhere but you can look at the blurstrike weapon enhancement from MiC. That looks reasonable.
Otherwise I'dd say as an attacker you gain the advantage of the +2 but not flatfooted since the enemy can see your arms and such.

 

[Dannyalcatraz]

I wouldn't give a set bonus. I'd give a big bonus for the first round- +5 or more- because the target just sees some moron waving his empty hands around, weaponless.

"Oh NOES! A KILLER MIME!"

However, once the first blow lands, I'd give them a single Wis based perception check- IOW, Spot- each subsequent round to let them reduce that bonus by 2 per success, to a minimum of +1, as they gauge the weapon's real dimensions. (I'd have to think a bit about setting the DC for that check, though.)

Yeah, its a bit of bookkeeping, but it has a good feel to it.

Of course, I'd also let someone actually able to see the sword negate the bonus entirely- without making any Spot checks- and actually get a +1 to their first attack vs the guy wielding the invisible weapon as he lures him in (with a successful Bluff check).

 

[Theo R Cwithin]

I'm inclined to go with the +1 to attack suggested by Dandu, mainly because it's simple. And perhaps even that fades after a few rounds (12-opponent_BAB, min 1, or something) as he figures it out. Maybe let it always grant a +2 bonus on feint checks or something?

Unless of course the guy has an invisible sword in the same way I have an "invisible friend", in which case you should just smile and back away slowly.

 

[Dandu]

Even if the enemy "figured it out" he still wouldn't know the exact shape of the sword.

 

[Dannyalcatraz]

Right, which is why the invisible weapon has a minimum bonus of +1 in my proposal.

 

[irdeggman]

A spot check of 20 allows you to be aware of an invisible creature near you, but not pinpoint it.

Perhaps a spot check of 20 -1 per round to figure it out.

Give a +1 to hit until the spot check is made.

This could reflect noticing how the attacker is gripping or using the weapon (which could give an idea of its size and reach) as well as the ending body position after the swing.

 

[Animal]

as an alternative, before each strike opponent rolls a spot check (DC 15 or so). if he doesn't beat the DC he is denied dexterity bonus to his AC for that strike.

 

[shadyizok]

Or we ignore all these dificul rulings and just go with the DMG:

When in doubt, remember this handy little rule: Favorable conditions add +2 to any d20 roll, and unfavorable conditions penalize the roll by –2. You’ll be surprised how often this “DM’s best friend” will solve problems.