From Atlas:

“A cult who have dedicated themselves to a fiend referred to as the Heavenly Demon wants to help him ascend to god hood. Over a year ago in campaign they enacted a plan to create a portal between the demon realm and the world they live in, allowing the Heavenly Demon and his subordinates to flood into the world with an army of demons, hell bent on destroying it. The party has been tasked by a deity to put a stop to the world destruction.

The Heavenly Demon and many of his subordinates are a new kind of Fiend i made for my campaign called Asura. They were once people who were killed violently and passed onto the afterlife filled with anger, hatred and regret. These feelings transformed them into Asura when they arrived in the Demon Realm. These Asura can only be truly killed if their mortal bones are found and cleansed, requiring the party to solve the lingering feelings of the Asura.

At this point in the campaign, the party were given an oracle that the bones of one of Bellona, one of the Heavenly Demon’s top subordinates, was in the vault of a demon cultist that the party have had conflicts with in the past. They party had to find, retrieve and cleanse the bones before Bellona attacked the capital city of the Empire the party lived in…”

“…The party had a lot of trouble with stealth, its the kind of thing that they usually are not good at. I have given them spy type quests before in the campaign, which they botched completely, getting them in a lot of trouble. I was hoping that they had learned from their mistakes and approached things more carefully this time.

They started with buying the blueprints to the basement maze from the local theives guild, paying extra to keep their purchase out of their enemies ears. I designed the blueprints to be somewhat incomplete. It would show them the path to take to get to the vault, while leaving out some of the extra areas; depending on the path they take, they could run into some trouble or discover points of interest. They initially intended to enter through the Warehouse, an area described as a place where people hear strange noises, and find it difficult to approach. Within the warehouse were 2 big portal to different Abyssal worlds where the cultists were collecting demons to use for their schemes. Due to the nature of the portals, the party were constantly suffering from confusion, causing one of them to fall down an elevator shaft, alerting the guards below. Once the party member was rescued, and the guards dispatched, the party decided on a different entry point.

The party continued through the maze following the blueprints they had bought, and quietly knocking out any guards they came across. They arrived at the vault after disentegrating a hole in the wall and bypassing a puzzle with its own disentegration mechanics. Guarding the vault was a powerful demon who was a subordinate of Bellona, she was a marilith with charming eyes, and blades that can turn her foes to stone. By the end of the fight, two party members were petrified with no way of reversal on hand, despite this, the vault was open and the loot was free to be taken.

Unfortunately the party spent too long trying to figure out what should be taken, and a passing patrol of driders and Yugoloths discovered the hole they left in a wall nearby, causing the party to be captured, barring one who managed to slip away in the conflict.”