Fighting Shadow Demons

[YASD]

Ok, so my GM likes to throw shadow demons at us http://www.d20pfsrd.com/bestiary/monster-listings/outsiders/demon/demon-sha dow

My first thought is how is this, given its defenses (yay incorporeal), touch based attacks, and bevy of spell-like abilities a CR 7 creature? My second is how do I fight such a beast?

Party is 3 characters, a semi-optimized God wizard (me), an optimized but non-ideally played ranger, and a badly built and played sorcerer? Right now we are level 11, but that just means that we get 2-4 of these added to a couple of bruisers.

Right now we just kinda bull through them eventually, but I was hoping for a more elegant solution.

P.S. we always fight these guys inside where at will deeper darkness is pretty much a guarantee.

for those who don't want to follow a link:

Shadow Demon CR 7
XP 3,200
CE Medium outsider; (chaotic, demon, evil, extraplanar, incorporeal)
Init +8; Senses darkvision 60 ft.; Perception +20

DEFENSE
AC 18, touch 18, flat-footed 14 (+4 deflection, +4 Dex)
hp 59 (7d10+21)
Fort +5, Ref +11, Will +7
Defensive Abilities incorporeal; DR 10/cold iron or good; Immune cold, electricity, poison; Resist acid 10, fire 10; SR 17
Weaknesses sunlight powerlessness

OFFENSE
Speed fly 40 ft. (perfect)
Melee 2 claws +11 touch (1d6 plus 1d6 cold), bite +11 touch (1d8 plus 1d6 cold)
Special Attacks pounce, sprint, shadow blend
Spell-Like Abilities (CL 10th)
At will—deeper darkness, fear (DC 18), greater teleport (self only) telekinesis (DC 19)
3/day—shadow conjuration (DC 18), shadow evocation (DC 19)
1/day—magic jar (DC 19), summon (level 3, 1 shadow demon 50%)

STATISTICS
Str —, Dex 18, Con 17, Int 14, Wis 14, Cha 19
Base Atk +7; CMB +11; CMD 25
Feats Blind-Fight, Combat Reflexes, Improved Initiative, Lightning Reflexes
Skills Acrobatics +14, Bluff +14, Fly +22, Knowledge (local) +12, Knowledge (planes) +12, Perception +20, Sense Motive +12, Stealth +14; Racial Modifiers +8 Perception
Languages Abyssal, Common; telepathy 100 ft.

SPECIAL ABILITIES
Sprint (Ex)

Once per minute, a shadow demon increase its fly speed to 240 feet for 1 round.

Shadow Blend (Su)

During any conditions other than bright light, a shadow demon can disappear into the shadows as a move-equivalent action, effectively becoming invisible. Artificial illumination or light spells of 2nd level or lower do not negate this ability.

Sunlight Powerlessness (Ex)

A shadow demon is utterly powerless in bright light or natural sunlight and flees from it. A shadow demon caught in such light cannot attack and can take only a single move or standard action. A shadow demon that is possessing a creature using magic jar is not harmed by sunlight, but if it is struck by a sunbeam or sunburst spell while possessing a creature, the shadow demon is driven out of its host automatically.

[Eltacolibre]

Shadow Demon have frankly only one weakness, its the sunlight powerlessness. If your dm isn't giving you a chance to use it...well not much you can do really. They have resistances to virtually everything dr, immunity to a bunch of energy attacks, spell resistance etc...It's a very hard fight in total darkness.

[Ipslore the Red]

Heighten a continual flame until it dispels deeper darkness and renders Shadow Blend unusable. Make as many backups of the continual flame as you feel is necessary. Automatic bright light in just about every situation.

[Zotpox]

Shield and mage armor will help with AC.
Cold Iron Ghost Touch Wpns are a good idea as well.

[Anonymous Visitor 163 576]

Get the sorcery to learn magic missile or buy a wand. That will bypass incorporeal, though SR will still be effective.

Protection from evil will help saves ( good) and prevent magic jar control (essential).

And crazily enough, tiny hut will block them out, since it's a force effect. They can still try to blast you out with fear and shadow fireballs, but it' s a start.

Not much advice for the ranger, but a ghost touch weapon would be nice.

[Ipslore the Red]

There's weapon blanch (ghost salt).