Update
Last sunday, the battle took place... right after some delicious chocolate cake and some cups of coffee

At the beginning of the session I asked to put up the big battle map onto the table...
Goals of Team Evil aka the Cult of the Dragon (1x necromancer 11/wearer of purple 3, 1x cleric 9, 1x wizard 7, 1x very old red dragon, 14x gnoll rgr 2, 1x gnoll chief: bbn 4/ftr 4/rgr 2):
1) capture the vampiric brass dragon
2) survive the battle
3) kill as much adventurers, if goals 1 and 2 allow to do so
Team Evil does not know that the PCs are low on spells, nor they do know anything about the artefact (Klorr's Timepiece) that the cleric/pious templar carries.
The gnolls would immediately flee once the red dragon would be gone.
The adventurers and their pseudodragon familiars left the cavern not tightly packed (which was good for them), the half-golem in front, the two brass dragon youngsters (one vampiric dragon, and his younger brother) being airborne already, circling above the group. They were still protected by
Resist Fire (30 pts), which helped a lot. But they were very low on spells. One PC is a lycanthrope, and it is her first full moon
In the surprise action, the very old red dragon Sjachixen - prepared with a range of protective spells:
Disguise Self (as a Black Dragon: gives a bonus to Hide in a dark night; and I don't have a gargantuan red dragon miniature

),
Protection from Cold, Resist Acid, Stoneskin, Shield, Protection from Law, See Invisibility, Greater Invisibility, Death Ward - cast
Evard's Black Tentacles ("EBT", CL 13) into the center of the group. In the spell's area were the warmage, the wizard/enlightened fist, the fighter, and the ftr/mnk/druid, including their pseudodragon familiars. Except for the ftr/mnk/druid, THEY ALL FAILED their grapple checks!!! The half-golem, the mnk/clr/pious templar and the two brass dragons were outside the area. The gnolls started to fire arrows, the NPC very young brass dragon is hit twice.
Round 1: roll initiative.
- The cultists just readied actions to counter any sort of teleportation, they would not play a role in the coming fight, though.
- the druid leaves the EBT area, and dismisses her familiar (standard action, works similar as a paladin's special mount)
- the enlightened fist succeeds her grapple check and leaves the EBT area
- Sjachixen breathes his
Blinding Breath, hitting the pious templar, the warmage, the fighter, the enlightened fist, the golem, and the remaining pseudodragons. Except for the pseudodragons (but which have Improved Evasion), now most of them MADE THEIR SAVES! I rolled up 111 damage, but only the ftr and the pseudodragons were blinded (most were badly beaten). I rolled the dragon's recharge time: he could breath again in the next round thanks to Recover Breath...
- the ftr dismissed her pseudodragon
- the pious templar tried to dispel the EBT but failed (the player rolled a 2), he then ordered the golem to search and attack any enemy archers and also ordered his pseudodragon familiar to fly to safety
- the golem marches in the direction of the gnolls, as ordered
- the NPC very young brass dragon got nervous and asked the enlightened fist what to do (he has not seen the PCs fighting a big dragon before...)
- the vampiric brass dragon located the invisible and camouflaged red dragon by chance via blindsense and breathed some fire. The flames shortly outlined the red dragon's silhouette, showing the PCs that something very big and hot is out there
- the warmage dismissed his pseudodragon, but had to stay in the EBT
- the gnolls fired the next volley (no damage)
Round 2:
- the druid decided to find the enemy archers and moved towards the gnolls, finding one and killing him
- the enlightened fist dismissed her familiar
- Sjachixen moved, used another
Blinding Breath as a fly-by attack, hitting again the pious templar, the ftr, and the warmage. I rolled 89 damage only, but the warmage and the ftr failed the saves. The red dragon now felt his breath power was a bit exhausted: recharge time 3 rounds.
- the ftr succeeded her grapple check and stumbled out of the EBT area (she was close to its border anyway)
- the pious templar moved to the blinded ftr and cast
Remove Blindness
- the golem spotted a gnoll archer and cut him in half
- the NPC brass dragon searched the enemy archers as well, spotted two of them hidden in a gully, and incinerated them.
- the vampiric brass dragon has lost track of Sjachixen, and decided to delay
- the warmage succeeded his grapple check and just made it outside the EBT area
- the gnolls kept on firing, the lycanthrope (the druid) is hit (I rolled a 20) and now turns into a weretiger (the moon light was covered by ash clouds from the volcano, so I decided that damage starts the transformation)
Round 3:
- the weretiger druid turned towards the gnoll that hit him, ripping him apart
- the enlightened fist cast
See Invisibility, and spotted the Sjachixen
- Sjachixen cast
Antimagic Field, became visible, and landed in front of the pious templar and the warmage. The guys now face the dragon and the EBT partly blocks their retreat path.
The players were quite shocked when I put that gargantuan black dragon "miniature" on the battle map

It made clear that this dragon IS business.
- the vampiric brass dragon charged towards Sjachixen, provoking an AoO. He was hit, but damage was low (thanks to DR 10/silver). The vampiric dragon did not hit Sjachixen.
- the ftr activated her Boots of Flying and moved into charge position
- the pious templar considered using the artefact which would allow him to age Sjachixen to death (takes 2 rounds). The artefact is wholly evil, and the pious templar is (still) LG. He decided not to use it, but moved away from the red dragon (no AoO left for Sjachixen)
- the golem searched for more enemy archers
- the NPC brass dragon found another gnoll, but had no further attack action
- the warmage drew a potion of
Remove Blindness, stumbled back into the EBT (and out of the AMF), made his grapple check, and consumed the potion.
- the few remaining gnoll archers moved and fired a few arrows (no damage)
Round 4:
- the weretiger run away into the darkness, hunting more gnolls
- the enlightened fist cast
Mordenkainen's Disjunction, and successfully dispelled Sjachixen's
Antimagic Field, but turning him invisible again in the process.
- Sjachixen (incorrectly) assumed that the party seems too well prepared, has enough power to dispel her wards, and is now positioning for melee combat. He attacked the vampiric brass dragon successfully, snatched him, and started to fly up, snarling: "I leave for now, I have my prize."
- the ftr followed Sjachixen (better: she followed the still visible vampiric dragon), but she could not keep up with the big dragon's speed
- the pious templar could not do much
- the golem did not find more gnolls
- the NPC brass dragon desperately followed Sjachixen (who has his elder vampiric dragon brother in his grasp)
- the vampiric brass dragon made escape attempts, and noticed that Sjachixen was protected against negative energy and potentially domination as well. Now a plan came to his mind... He told the pursuing ftr and his younger brass dragon brother: "Don't fight, follow my tracks..." He spoke this words in Chondathan language, hoping that Sjachixen would not understand (he did not).
- the warmage used the time to heal a bit
- the remaining gnolls broke and fled
Round 5:
- the enlightened fist had not heard the vampiric dragon's words, she cast
Earthbind (I feared that this would come) on Sjachixen, but she did not overcome his SR (she rolled a 2, a 3 would have been enough...

)
- Sjachixen realised that he is now in potential danger of loosing his flight ability and decided to move away as fast as possible, taking his "prize" with him
- the ftr returned to the party
- the NPC brass dragon followed Sjachixen in a safe distance for a while
- the vampiric dragon feinted some escape actions, but he was willing to get carried away to find out more. And Sjachixen's wards would run out eventually...
- the cultists have observed the battle from a camouflaged place (covered by an
Illusory Wall), then they teleported back to a meeting point, hoping that Sjachixen would show up with the captive vampiric dragon.
I have ruled that AMF begins at the "surface" of a creature and extends 10 ft. in every direction. This is not strictly RAW, but it avoids strange effects that big creatures are only partly protected by their own AMF.
Next session is next sunday, and the party will meet the Cult of the Dragon again.
EDIT: Stupid typos...