Mirror Image verses Blindsight

[ForceUser]

My main play character is a Bladesinger who fights dragons a lot. The Bladesinger spell list includes improved invisibility, blur, displacement, and mirror image - all useful defensive spells. However, I'm confused over whether or not they are at all useful verses dragons and other creatures with blindsight. I don't have a copy of the MM handy, but under the red dragon listed in the back of my PHB, the description of blindsight states:

Blindsight (Ex): The dragon can ascertain creatures by nonvisual means (mostly hearing and scent, but also by noticing vibration and other environmental clues) with a range of 210 feet.

Seems pretty straightforward. This implies that purely visual spells such as improved invisibility are negated by blindsight. But I bolded hearing for a reason. Here's an excerpt from the description of mirror image:

Several illusory duplicates of you pop into being, making it difficult for enemies to know which target to attack. The figments stay near you and disappear when struck.
Mirror image creates 1d4 images plus one image per three caster levels (maximum eight images). These figments separate from you and remain in a cluster, each within 5 feet of at least one other figment or you. You can move into and through a mirror image. When you and the mirror image separate, observers can't use vision or hearing to tell which one is you and which the image. The figments may also move through each other....
....An attacker must be able to see the images to be fooled. If you are invisible or an attacker shuts her eyes, the spell has no effect....

Okay, so I'm confused. If you're fighting a creature with blindsight in a lighted area, does blindsight still negate mirror image? It's the line "...can't use vision or hearing to tell..." that's bugging me. Since blindsight relies partially on hearing, and you can't use hearing to see through mirror image, is blindsight then ineffective against this spell? Also, another thing, although it specifically describes mirror image in visual terms, the PHB also suggests that the illusion is auditory as well, meaning that not only do the images look just like you, but they sound just like you too. In effect, you in stereo. So why then would a blinded person (or a creature using blindsight) not be fooled since your images are all making the same noises you're making?

Moving on. In the description of blur, we read:

Opponents who cannot see the subject ignore the spell's effect...

Okay, I'll buy that. But in the description of displacement, we find:

Emulating the natural ability of the displacer beast, the subject appears to be about 2 feet away from his true location. He benefits from a 50% miss chance as if he had full concealment. However, unlike actual full concealment, displacement does not prevent enemeis from targeting him normally. True seeing reveals his true location.

Again, I don't have my MM handy, so I don't know how the displacer beast's ability functions. But the question I'd like to ask is how does the displacer beast appear to be elsewhere? Visually, certainly. Auditorially? Do you always see the displacer beast in one spot and hear him just a little away from that spot? If so, does displacement work verses blindsight?

These are relevant questions to the longterm health of my character. Any insight or Sage rulings would be appreciated

edit: darn vB codes

 

[Gromm]

I'd say the dragon is immune to the Mirror Image. If the players don't like it the dragon can close his eyes and become immune (the spell description actually say that counters it).
From what I recall Blur and Displacement are also countered by Blindsight (for obvious reasons). Though one could say Displacement copies sound as well and isn't neccessarily countered, though there isn't much to back this up.

MM p60-Displacer beast
"A light-bending glamer continually surrounds a displacer beast....Any melee or ranged attack directed at it has a 50% miss chance unless the attacker can locate the beast by some means other than sight..."

So displacer beast displacement is neutralized by blindsight, seems logical that the spell is too (esp since it says its just like a displacer beast).

 

[Caliban]

Again, I don't have my MM handy, so I don't know how the displacer beast's ability functions. But the question I'd like to ask is how does the displacer beast appear to be elsewhere? Visually, certainly. Auditorially? Do you always see the displacer beast in one spot and hear him just a little away from that spot? If so, does displacement work verses blindsight?

These are relevant questions to the longterm health of my character. Any insight or Sage rulings would be appreciated

edit: darn vB codes

from the SRD:

BLINDSIGHT

Some creatures have the extraordinary ability to use a nonvisual sense (or a combination of such senses) to operate effectively without vision. Such sense may include sensitivity to vibrations, acute scent, keen hearing, or echolocation. This ability makes invisibility and darkness (even magical darkness) irrelevant to the creature (though it still can’t see ethereal creatures). This ability operates out to a range specified in the creature description.

Blindsight never allows a creature to distinguish color or visual contrast. A creature cannot read with blindsight.

Blindsight does not subject a creature to gaze attacks.

Blinding attacks do not penalize creatures using blindsight.

Deafening attacks thwart blindsight if it relies on hearing.

Blindsight works underwater but not in a vacuum.

Basically blindsight lets you "see" without using light. It negates any effect which relies on visual perception.

Mirror Image, Blur, Displacement, Invisiblity, etc. would be negated by blindsight.

 

[ForceUser]

Darn. That means I'll have to stick with haste, shield, and fire shield to deal with those pesky dragons

 

[Xarlen]

No, it sucks when one of your players has a Bat familiar, and that blindsighted little sucker can detect enemies invisible, in darkness, etc.