A lot of how good this encounter is going to be is going to come down to whether or not the GM is any good at playing Pinhead. Really, I’m not even sure how to give advice to that effect, beyond “watch Hellraiser II and III and do it like that. Ignore everything that isn’t Pinhead.”
Summary: The local Chaos warlord fears that the Imperium will soon advance and claim his town, executing him for heresy as added insult. He has a plan to keep them at bay, however: Summon a daemon from an evil Rubik’s cube. What could possibly go wrong?
Discovery: The first night the characters enter the village, the warlord summons the daemon. If the characters have, for some reason, decided to immediately begin stalking the local warlord in his manor, then they will see the ritual and potentially be able to disrupt it. It only takes a few minutes to complete, and involves rotating the components of the puzzle box (more complex than a literal Rubik’s cube) into a specific configuration. If the characters interrupt the ritual, then that’s the end of it. The warlord has no other tricks up his sleeve besides having some Red Guard at his beck and call to sic on the characters.
If the characters observe the ritual but decide not to intervene, the daemon will be successfully summoned. The warlord attempts to bargain with the daemon, who immediately attacks, slaughtering the warlord and his guards. It is essentially impervious while its puzzle box is still in the summoning configuration, but it cannot touch the box, neither directly nor indirectly (i.e. through a cloth or glove), so instead it leaves the manor to begin a rampage through the village.
If the characters didn’t make any immediate efforts to stalk the local warlord, the start of this rampage will most likely be their first indication that something’s up.
Exploration: A successful Difficult(-10) Forbidden Lore (Daemonology) or Hard(-20) Forbidden Lore (Heresy) check will reveal the origins of the daemon, and that its puzzle box must be recovered and reconfigured into the banishing configuration in order to render it vulnerable to mortal weapons, eliminating its Daemonic(20) trait. Searching the manor from which it emerged will turn up the puzzle box with an Ordinary(+10) Awareness test if the search is being conducted under time pressure (for example, if the daemon is still attacking), and succeeds automatically if there’s no time pressure. The puzzle box is still just lying on the floor in the library, knocked off the table during the fracas after the daemon’s initial summoning. The daemon can’t hide it and no one else has come here since, what with the daemon killing everyone nearby. If the characters join the three or four remaining Red Guard attempting to fight the daemon in the town, those Red Guard will flee after it becomes clear their weapons are useless, and if the characters flee with them, one of them will recount how the daemon was summoned from the puzzle box.
The puzzle box can be solved with a Difficult(-10) Logic check, or else a Very Hard(-30) Forbidden Lore (Daemonology) check or an Arduous(-40) Forbidden Lore (Heresy) check to just know the combination in advance. The Forbidden Lore checks can only be attempted once per character (you either know the combination or don’t), but the Logic check may be attempted as many times as any character likes, with each check taking five minutes, or a single full action at a -20 penalty if, for example, the daemon is trying to murder them right at that instant and they need to solve the thing in a hurry.
The daemon has a supernatural awareness of where the puzzle is located and if its pieces are being rearranged, although he cannot see any of the puzzle box’s surroundings nor who is manipulating it. This means that it will immediately begin pursuing the box when it detects someone moving or manipulating it, but will not know what to expect when it arrives there and has no special ability to navigate to the box’s location if the way is confusing. It knows how far away the box is and in what direction, but not necessarily how to get there.
Confrontation: When solved into banishment configuration, the puzzle box revokes the daemon’s Daemonic(20) trait, at which point it goes from nearly impervious to most sources of damage to being slightly more intimidating than the heavy thugs with chainaxes characters have likely been fighting since their first couple of sessions. Defeating the daemon without solving the puzzle box is significantly harder, however force weapons, holy weapons, psyker powers, and other daemons can ignore its Daemonic(20) damage reduction, and weapons that can reliably deal more than the 24 points of damage reduction the daemon has on tap will be able to whittle the daemon’s health down. Melta weapons, krak missiles, autocannons, and with a bit of luck an eviscerator can all plausibly damage the daemon even when fully protected. A chimera with a multilaser or autocannon (tragically, the town’s local chimera has a heavy bolter on the turret, a heavy stubber on the pintle, and a heavy flamer forward facing, none of which are very likely to hurt the daemon at its fullest power, but autocannon or multilaser chimeras aren’t all that uncommon if the characters can call on reinforcements from other towns) or the standard cannon of a Leman Russ or basilisk would also be able to wear the daemon down.
In the event that no such option is available and the characters are forced to retreat, the daemon will wipe out the whole town, survivors fleeing into the wilderness. It will not leave the hex, instead remaining within a few kilometers of its puzzle box to ensure its safety.
Rewards: The daemon will not respond to any attempt at bargaining while its puzzle box is in the summoning configuration or completely scrambled, however it will become very open to negotiation with anyone who has the puzzle box configured for banishment. Indeed, if the one holding the box in banishment configuration makes any demand that the daemon kill or maim someone, the daemon will obey without any need for a check at all provided the one holding the box puts it back out of banishment configuration in exchange. The daemon utterly loathes being commanded in this way, but it will comply and attack any targets it is directed to so long as its would-be master still has the box in their possession. The daemon will be happy to retaliate when, for example, their master is sleeping, if they do not have a watch posted. It will not obey any commands unless the box is back out of banishment configuration (even if only one piece has been rotated out of place, which could thus be quickly twisted back into banishment configuration were the daemon foolish enough to try and immediately renege), but if the box is in banishment configuration, the daemon will lurk nearby, hoping to find an opportunity to kill the owner, which means the box can be placed into banishment configuration to keep the daemon vulnerable whenever its services are not needed and it will not immediately rebel.
If the daemon is thwarted (through killing it or forcing it to submit using the banishment configuration) before the town is destroyed, then the lack of warlord (in the very likely event that the warlord was killed before the daemon was defeated) leaves it leaderless, at which point anyone with the goons to spare can seize it. Anyone installed as ruler gains 1d10 Influence, and anyone associated with the new ruler gains 1d5 Influence. The town can provide any weapon or service rare or cheaper, and anything else at all scarce or cheaper. If the characters or one of their allies rules the town, they can levy the town for 2 Influence to automatically succeed on a requisition check.