Quick Blindsense question

[AlanBruce]

Greetings! I know that Blindsense is Blindsight's little brother, so to speak. From what I gather, a creature with this quality does not need to make spot and listen checks if someone is within their blindsense area. I believe I udnerstand how it works, but to get an excat ruling, I propose the following scenario:

Monster with blindsense walks up and down a 10ft wide corridor. Stealthy rogue hides and moves silently through the corridor, eventually passing the monster. Would the rogue get some AoO an initiative roll, or some such? Or would the monster with blindsense actually have to roll vs. his Hide and MS check?

If same rogue in exact same scenario is invisible, would the rules differ?

Thank you in advance.

[supermonkeyjoe]

Blindsense

Other creatures have blindsense, a lesser ability that lets the creature notice things it cannot see, but without the precision of blindsight. The creature with blindsense usually does not need to make Spot or Listen checks to notice and locate creatures within range of its blindsense ability, provided that it has line of effect to that creature. Any opponent the creature cannot see has total concealment (50% miss chance) against the creature with blindsense, and the blindsensing creature still has the normal miss chance when attacking foes that have concealment. Visibility still affects the movement of a creature with blindsense. A creature with blindsense is still denied its Dexterity bonus to Armor Class against attacks from creatures it cannot see.

IF the rogue is just hiding and moving silently the monster would automatically detect him then the rogue is within range of the blindsense, if the rogue is invisible the monster would know what square he's in but still suffer the 50% miss chance as the monster wouldn't actually be able to see the rogue.

[AlanBruce]

Thnak you for clarifying that! So would the rogue, who has no idea of the monster having blindsense and sneaking past the creature get a surprise attack? Or would initiative be rolled?

[TuggyNE]

The monster might get a surprise round, but that seems unlikely; I think you'd just roll initiative (both combatants are aware of each other, presumably; the only thing the rogue doesn't know is whether the monster has noticed him yet). Incidentally, the monster wouldn't get AoOs, since
You can’t execute an attack of opportunity against an opponent with total concealment, even if you know what square or squares the opponent occupies.

[mattie_p]

Also of interest to the rogue is that the rogue gets to apply sneak attack dice to any and all attacks, so long as the target is only using blindsense to detect them.


A creature with blindsense is still denied its Dexterity bonus to Armor Class against attacks from creatures it cannot see.

Once the creature spots (the skill, I mean) the rogue, it regains dex to AC until the rogue successfully hides in some fashion.

[Newoblivion]

Hmmm.. at the MMI if you read about the bat it say that opponents still have 100% concealment against a creature with blindsense. How so? if I know that you are in sqaure X I can try to swing my weapon and hope to hit you (just like any invis creature). Why the 100%? :S

[juicycaboose]

100% concealment means 50% miss chance, not 100% miss chance

[mattie_p]

Hmmm.. at the MMI if you read about the bat it say that opponents still have 100% concealment against a creature with blindsense. How so? if I know that you are in sqaure X I can try to swing my weapon and hope to hit you (just like any invis creature). Why the 100%? :S

This is only if they are visually undetectable via other senses.


Invisibility
Visually undetectable. An invisible creature gains a +2 bonus on attack rolls against sighted opponents, and ignores its opponents' Dexterity bonuses to AC (if any). (Invisibility has no effect against blinded or otherwise nonsighted creatures.) An invisible creature's location cannot be pinpointed by visual means, including darkvision. It has total concealment; even if an attacker correctly guesses the invisible creature's location, the attacker has a 50% miss chance in combat.

If a creature has blindsense as well as other detection methods to pinpoint and/or see the otherwise hiding/stealthy character, then they all overlap until they are either still "visually" undetectable with the miss chance or spotted.

[Person_Man]

As a side note, if you happen to be playing a character that's going to be Invisible a lot you should really take the Spectral Skirmisher Feat from PHBII. While invisible, a creature using a melee attack against the square you occupy provokes an attack of opportunity from you. Basically Robilar's Gambit, but with no penalties, assuming you're Invisible.

On the flip side, if your DM is fond of Invisibility, buy a Blindfold of True Darkness from Magic Item Compendium, for cheap See Invisibility.

[AlanBruce]

Thank you all for the great responses! The rogue in question has no means to go invisible (as per the spell), relying on his hard earned ranks to hide and move silently. The monsters have blindsense and are patrolling tight corridors, so rolling initiative seems like a nasty outcome. Odd, however, although they can sense him and attack accurately, he still can hide on his turn to get a sneak attack. A fair trade.

[mattie_p]

Visually undetectable works for hide as well. So long as the rogue is successfully hiding (requires either cover or concealment) he gets sneak attack, as he is visibly undetectable and therefore effectively invisible (http://www.d20srd.org/srd/conditionSummary.htm#invisible).

[Piggy Knowles]

As a side note, if you happen to be playing a character that's going to be Invisible a lot you should really take the Spectral Skirmisher Feat from PHBII. While invisible, a creature using a melee attack against the square you occupy provokes an attack of opportunity from you. Basically Robilar's Gambit, but with no penalties, assuming you're Invisible.

On the flip side, if your DM is fond of Invisibility, buy a Blindfold of True Darkness from Magic Item Compendium, for cheap See Invisibility.

Combine with the Evasive Reflexes feat, which lets you take a five foot step in place of an AoO. Now, when they locate you via blindsense or whatever and attack your square, you move five feet away - and it explicitly resolves before their attack.