I run a campaign with very smart players who have found a way to make a ninja ridiculously overpowered.
Using the vanish ninja trick, they vanish, move somewhere, then on the next round do a full round sneak attack(breaking the vanish) with rapid shot and then vanish again at the end of the round. They are doing 3-4d6 with each shot rendering most encounters a massacre.
Are the rules being used right?
After the first attack they are no longer invisible so should not get sneak damage.
Okay. I think I've found some reference to that. But the vanish part is okay?
Yes, the whole point of vanish is it gives the ninja a reliable way to get sneak attack on their own.
So they full attack from invisibility. When they break stealth they only benefit from invisibility for the first attack(Meaning their opponents are denied dex only for the first attack even with Rapid Shot). All other attacks don't benefit. Then as a swift, they blow the ki to re-invisible themselves.
It's not broken at all really:
-Ki is a limited resource. Like, really limited. If they're burning one every round, they'll be out of it in a single combat unless they're high level. And if they're high level its a non issue cause...
-At level 10, a Ninja can get Greater Invisibility with the Invisible Blade Trick, meaning they never leave invisibility at all and all thier attacks benefit from said invisibility. So, comparatively, burning a ki a round for invisibility to only get one attack that benefits is nothing.
Thanks guys. Found some links to that.
The ability has its limitations:
Ki costs, as mentioned.
Vanish takes a swift action, meaning they can't use any other swift action abilities in any round they want to disappear.
This type of sneak attack doesn't work on all enemies - for example ghosts, oozes and barbarians with Uncanny Dodge are immune, as is anything with Blindsight or See Invisibility (more common at high levels). Low level spells like Glitterdust are an effective counter.
Just wait till the ninja gets Greater Invisibility for a ki point at level 10. He will be invisible in every round of combat from the rest of the campaign.
Well... until something that can see through invisibility goes and eats him.