I had to improvise the adventure last time; while my Sandbox World Generator told me what was in the square it didn't provide all the details. Between sessions I fleshed out the cult and discovered that it had a name, in addition to a signature calling card in the form of golden crossbow quarrels. Eventually I'll publish this adventure on DriveThruRPG like all the rest. The only reason The Lake of Ill Repute isn't up there is that they haven't finished going through it yet.
The Brotherhood of the Golden Arrow
The party (retroactively) marveled over all the golden crossbow quarrels they looted off of the bandits that had attacked their camp, until the Wizard made his Appraise check and realized they were just well-polished bronze.
The party sent in Sir Rattles, again to no effect. Now that they had two independent reports that the tunnel was empty it only took them twenty minutes to raise the courage necessary to actually enter the tunnel, and even then they only went in because the Barbarian got tired of "strategizing."
Once inside they were greeted by ten skeletons. The toad had not noticed them because they don't move, breathe, emit heat, or otherwise appear differently than dead bones, and they hadn't attacked Sir Rattles out of professional courtesy. Undead make excellent ambushers.
The Barbarian smashed one while the Cleric looked up the rules on Turn Undead. A few dice rolls later and all of the skeletons collapsed, utterly destroyed by the puissance of the Cleric's holy words. Sadly this cleansing of the unnatural also included Sir Rattles (a tip o' the hat to the Bard for pointing that out!). It turns (haha) out that the Cleric had missed the latest dungeon runs, so no one was aware of just how potent he was against low-level undead.
After that they briefly examined a closed door but decided to push further into the cavern. They didn't get very far before being greeted by a company of guards with a spell-casting senior office. Twenty cultists, fighting in formation: the ones in front knelt defensively behind their shields while the back row fired over their heads with crossbows. The Ranger cleverly pocketed his light-stone and started sniping from the dark while the Barbarian charged; the Wizard and Druid summoned acid-spitting beetles; and the Bard and Cleric went down a side tunnel hoping flank the attacking group but instead ran into a smaller group which included an junior officer of the cult.
The absence of treacherous vegetation and the presence of spell-casters turned the battle around. Expecting the relentless slaughter of the previous engagement, the party found they had a fight on their hands. Fear spells were particularly useful, sending the the Ranger, the Bard, and the Barbarian (twice!) in and out of combat like yo-yos. The Barbarian made it all the way to the front line and slew three foes
in a single great blow before eating half-a-dozen quarrels and being
sent running by magic. Healing also paid off as the two cult spell-casters put men who had been incapacitated but not outright killed back into the fight; when the Barbarian came back half the men he had killed were alive again.
Finally the Druid decided to unleash the swarm. Thousands of spiders crawled up out of the sandy cavern floor, biting and stinging. Fortunately their poison weakened before it killed, so the men's shrieks of horror as they were devoured alive were slightly muted. The senior officer, revealing a sophisticated understanding spellcraft, got the swarm's attention and led it away from his men. This took him out of the fight but not out of the battle as he succeeded in healing himself several times even in the midst of the swarm. It was a fair trade, as concentrating on the swarm kept the Druid busy.
The advance party came back to the main battle, having been chased off by Fear after killing all but the junior officer in the side passageway. The Wizard called up another acid beetle after the first one exploded and dissolved several men's faces in acid. Fortunately this horrific sight was only poorly illuminated by torch-light so likely the party won't have too many nightmares. The Barbarian, operating off of courage rather than intellect, charged the line once again, and this time they broke and fled. Just in time, as the side passage was once again active after the officer had healed several casualties. The Wizard, Cleric, and Bard ran to deal with that while the Ranger followed the fleeing remnants of the main group. The Druid sat in a corner and concentrated fiercely on his swarm of vicious insects, no doubt struggling with remorse over the horrible deaths he had caused.
The junior officer in the side-passage turned out to be wearing decent armor (note to self: more bronze breastplates!). Half the party beat on him while the Wizard kept him dazed and yet he remained standing. The side passage did indeed join up with the other one, as both passages opened into a vast cavern. Which contained another entire company of troops, all bearing torches and charging the swarm.
The Ranger picked off a few men while they dealt with the spiders by beating their torches against the ground and occasionally the officer in the middle of the swarm. This bought the rest of the party enough time to finally finish off the junior officer. They looked up just in time to see the retreat stemmed by demonic authority. Which is to say, a nine-foot-tall demon bit the head off of one of the retreating men, and the other two decided to go back into battle. Not the typically recommended courage-inducing rally cry but it worked. Beside the demon stood the cult's leader, a wild-haired shaggy man in bronze armor and wearing a golden crossbow quarrel around his neck.
Everything froze in that movie-style magic where the really dramatic bits seem to take forever. (Meaning we broke for pizza.) After a surprisingly lengthy discussion which included checking the side-door for a defensible position (spoiler alert: it wasn't) the party decided to retreat, having run out of spells and hit-points. The cultists, for their part, were not about to take lightly an enemy who had caused so much slaughter, and advanced with caution, allowing our heroes to escape.
Outside, under the open sky, the party set their own ambush, hoping to bottle their pursuers up in the narrow tunnel. While the Wizard was asking if there likely to be any other entrances to the lair he noticed a company of men coming out of the ground about a quarter-mile away. Again the party chose retreat, heading west (back the way they had come). The cult pursued them, but not aggressively, as the party was walking into wilderness rather than towards the nearest city. At the banks of a river the cult stopped and watched them go.
But it was not retreat, merely a strategic advance to the rear. The party camped, healed their wounds, refreshed their spells, and came creeping back under the cover of darkness.
Now they found the entrances guarded by cultists armed with gongs. The Ranger tried some diversions (oddly including throwing a desert tortoise) and sniper fire, but only succeeded in setting off the alarm. Discouraged, the party began retreating again.
The cult did not let them go so easily this time. The Druid's hawk stared nervously at the sky as they fled. This time the Druid paid attention and realized they were being followed. Trapped on the open plain under a star-lit sky (the world of Prime does not have a moon, but it does have so many stars that clear nights are as illuminated as a full moon), stalked by a flying demon, they had few options. They stood in a circle, back to back, like heroes facing the horde. Soon enough a black cloud swelled up from the ground, resolving into the fearsome visage of the demon.
The party responded quickly, with spells and arrows. The monster continued to advance and the Barbarian bravely leapt forward to strike with his temporarily magic-blessed sword. The blow passed through the creature without harm; the Barbarian realized it was merely illusion.
The party lowered their arms but the damage was done. Those spells were wasted. Tense minutes passed as the demon's allies came into position. Again, crossbow quarrels flew through the night. In the darkness accuracy was difficult and it wasn't clear whom the battle of attrition would favor. Until the demon struck from behind.
The Cleric was its chosen target. He proved hardy enough to survive the claws and fangs, but the poisoned stinger in its tail left him as weak as a baby. The fighting men turned bows and swords on the creature and it immediately fled. But as they resumed their archery contest with the cultists, the demon returned, having been fully healed by unknown powers.
This time the Bard went down in a spray of blood, and only a timely spell from the Cleric kept him from bleeding to death in the grass. Once again the warriors drove it off. The Wizard luckily caught a hint of chanting. He quickly called up some illusionary lights and sent them forth, discovering the hiding cult leader (the only time I have ever seen Dancing Lights actually used). As the demon left his side to fly back to the battle, the Wizard starting summoning apes (apparently impressed by the 1d6+5 damage roll) and sent them to attack the leader.
Now the cult leader was well-prepared, having certain spells of devastating effect against human foes. Which unfortunately expressly did not include animals. He soon found himself wrestling in a most undignified manner with two apes and the Druid's wolf as the spell-casters charged him (the warriors were still occupied with the demon). The cult leader called his demon back to save him; it broke off and flew threw the air, snatching up the leader on its way.
Until the mess of animals pounced on him, sinking claws and fangs into flesh and holding on for dear life. It proved too much weight; as the warriors charged, the demon shrugged its shoulders and let go. It flew off into the night while its erstwhile master screamed for mercy. "I'll let you in!" he cried, hoping to buy mercy; the Wizard and Druid, unmoved, did not call off their beasts. Consequently by the time they got to the man he had been torn limb from limb.
The remains of the cultists fled after seeing (well, hearing) their leader so savagely destroyed. The party tallied up the enemy's losses and grimly resolved to end the threat of the demon once and for all. In the morning they marched east, covering the familiar ground they had already twice retreated over, until they stood at the mouth of the entrance, with vengeance on their minds and blood on their hands.