The maps depicting levels 1 through 5 of Castle Serastis appear on the inside covers of this book.
When the PCs approach the fortress, read:
Although any observer can tell that the castle’s construction is odd, a successful DC 15 Knowledge (architecture and engineering) check confi rms that the fortress exhibits traits of yuan-ti construction.
The keep makes up the bulk of Castle Serastis, though it contains none of the locations most important to the Vanguard.
When the PCs climb the stairs, read:
If Lieth succeeded in fleeing to the fortress after the encounter in area F, read:
The door (area K2) and the portcullis (if down) are formidable obstacles. Both are solid iron gilded with brass.
Iron Portcullis: 2 inches thick; hardness 10, hp 30, break DC 28; Strength DC 25 to lift.
CR 1; mechanical; location trigger; manual reset; Atk melee (); Search DC 22 (to fi nd the mechanism; the portcullis is obvious); Disable Device DC 20.
The damage applies only to creatures underneath the portcullis if it drops. Such creatures are knocked prone and held in place until the portcullis is lifted or they succeed on a DC 20 Escape Artist check.
If it is not already down, the portcullis might be triggered by the PCs’ actions in area K2.
When the PCs approach the doors, read:
Barred Iron Door: 2 inches thick; hardness 10, hp 60, break DC 38.
The doors are held shut by a system of winches and counterweights, and must be disabled or forced. A successful DC 22 Search check reveals a few thin openings around the door frame that allow access to the cables. A successful DC 22 Disable Device check causes the counterweights to release and the doors to creak slowly open.
The counterweight system is tricky. If the first Disable Device check fails by 5 or more, the portcullis in area K1 drops with a loud crash, potentially trapping PCs in the kill zone. Roll for random encounters as though the trapped PCs were inside the fortress. Any patrol appears from the base of the stairs and fi res at the PCs through the bars.
If all else fails, the PCs can wait until someone opens the door from the inside. If this occurs, they encounter a patrol of four yuan-ti purebloods (this counts as one of the eight pureblood patrols that can be encountered). Unfortunately, patrols depart by the main door only every hours.
When the PCs enter, read:
The winches control access to the central keep. The south winch opens and closes the great door (K2), while the north winch raises and lowers the portcullis (K1).
A shallow stair (barely more than a ramp) curves upward and around from the south side of the room, eventually leading to area K15.
Give the PCs time to take in the room from the doorway if they have been cautious enough to advance unseen. However, any character who enters the hall triggers the tactical encounter.
Tactical Encounter: K3. The Great Hall, page 30. The battle with Prath and the guardian makes substantial noise. As long as the PCs remain in this area, check for random encounters every 5 minutes. (If the party leaves this area and returns more than 1 hour later, random encounters revert to normal.)
Random Encounters: Roll for a random encounter in area K15 any time the PCs pass through area K3. If an encounter occurs, the guards in K15 snipe from above. Characters adjacent to the railing in K15 have line of sight to anyone below, as described in area K15 (page 15).
Treasure: In addition to Prath’s possessions (see the tactical encounter), anyone examining the pool sees a 12-inch-wide silver inlay at the bottom in the shape of a coiled serpent. A successful DC 22 Search check notes chipped stone around it, revealing that it can be pried off (a DC 15 Strength check). The silver icon is worth 1,500 gp.
Illumination: Continual fl ame wall sconces shed bright light throughout this area.
When the PCs enter, read:
Random Encounters: Any random encounter here is with a human or yuan-ti patrol on dinner break. Its members are gathered at a table, though one has a 20% chance of being found in the kitchen (K5). This character appears in 2 rounds if combat breaks out.
The abominations do not eat here. If a group with an abomination is indicated, reroll.
Tables and Chairs: Squares occupied by tables or chairs are considered difficult terrain, and tables provide cover to adjacent characters. A character can step up onto a table as a move action, gaining a +1 bonus on melee attack rolls against those on the floor. Two characters working together can tip over a table to provide cover against ranged attacks.
Illumination: Continual flame wall sconces shed bright light throughout this area.
When the PCs look in, read:
No random encounters occur in this room except as noted in area K4. A small grate in the fl oor (Spot DC 10) serves the same purpose as the grate in the dining room.
Treasure: Hanging on hooks next to the slabs of meat are a half-dozen oversized knives and cleavers. Though they appear nondescript, they are sturdy enough to serve as improvised weapons (treat as daggers and handaxes).
K6. TORTURE CHAMBER The doors of this room are locked.
Illumination: Continual flame wall sconces shed bright light throughout this area.
When the PCs open the doors, read:
The builders of Castle Serastis placed the torture chamber on the level above the cells, so that the castle’s masters would not have to enter the dungeons for interrogations or entertainment. The iron grate allows spilled blood to fl ow into the same series of pipes as those found in K4 and K5. A shallow stair in the north side of the room leads to the cells below (K9).
Random Encounters: The fi rst random encounter occurring here involves the torture of a prisoner (Rollin, from cell K10C). His tormentors want no information from him; they are merely amusing themselves. If rescued, Rollin tells the PCs of the other prisoners below, warns them of Yensurros (see K9), and can offer any of the information described in K10.
Any random encounters here after the PCs free the prisoners from the dungeon involve patrols simply passing through the area.
Torture Devices: Squares occupied by torture devices are considered difficult terrain and provide cover to adjacent characters. Anyone bull rushed or otherwise knocked into a torture device takes points of additional damage from its spikes,blades, or other external trappings. K6A. Temporary Cells: The locked doors to these cells feature small barred windows.
If the PCs look within, read:
Prisoners awaiting torture are moved from the cells below into these holding pens. The yuan-ti believe (correctly) that hearing the screams of those who go before them weakens the prisoners’ will before interrogation even begins.
When the PCs enter, read:
Once one of the most vital areas of Castle Serastis, the meeting hall has seen little use in the past few months. The Cult's servants know their assignments, and any councils now take place in the castle’s shrines.
The secret door opens onto a twisting passage. This slopes down to the passage outside K13 and up to the passage connecting the barracks (K16).
Hidden Pit Trap: CR 3; mechanical; location trigger; manual reset; DC 20 Reflex save avoids; 30 feet deep (, fall); multiple targets (fi rst target in each of two adjacent squares); Search DC 24; Disable Device DC 18. Characters falling into this pit end up in cell K10F.
This pit is activated by a hidden switch on the lectern (Search DC 24), and was used to publicly punish cultists whose faith was found lacking. Though the trap has not been used in some time, the patrols know to avoid it. The trap is triggered by 40 pounds or more of pressure, but anyone who searches the podium and fi nds the switch can deactivate it (no Disable Device check needed).
Dais: Characters on the dais gain a +1 bonus on melee attack rolls against those on the floor or a lower step
When the PCs look in, read:
Tactical Encounter: K8. The Lesser Shrine, page 31.
Diplomacy: If the PCs speak to Chavakuth, he reveals the following information as part of a careful and tentative backand-forth. Read the following in response to player questions, extrapolating as appropriate. (Chavakuth’s halting speech results from his speaking Common only infrequently. If one of the PCs speaks Abyssal, Draconic, or Druidic, alter it accordingly.)
Though Chavakuth hates the poison dusk lizardfolk and is willing to aid the PCs against them, he will not turn traitor against the Vanguard as a whole. Any attempt to make him do so results in violence.
If the PCs agree to his bargain, Chavakuth gives them specific directions to the poison dusk guards in the passage (K18) to the Tower of the Way. He also directs them to one of the wandering poison dusk patrols (so that the next random encounter is with a poison dusk group).
The PCs can obtain additional aid from Chavakuth, but only after bringing back proof of having slain at least one group of poison dusks and promising to slay another. If one of the party is injured in the fi rst raid, the druid offers his potion of cure moderate wounds as a boon for the PCs’ service. If pressed for greater assistance, he agrees to let the characters rest in the shrine for one night. Additionally, if the PCs succeed on a DC 23 Diplomacy check (again with a +3 circumstance bonus for speaking Draconic), he reluctantly tells them of the prisoners in the cells below (K9 and K10), showing them the secret door in the south wall of the shrine.
Allowing the prisoners to escape is the closest Chavakuth comes to betraying the Vanguard. He refuses any requests beyond that, and attacks if the PCs attempt to force the issue.
The passage behind the secret door slopes downward, providing access to K13 and to a hidden exit from the fortress.
Ad Hoc XP Award: If the PCs deal with the encounter diplomatically from beginning to end, award them XP as if they had successfully overcome a CR 6 encounter.
When the PCs approach the fortress, read:
Read aloudMore details of the castle’s bizarre structure become clear as you approach, though its exterior remains shrouded in layers of shadow. The central keep boasts a balcony near the top, adorned with serpentine figures. Great stone steps some 20 feet wide lead up to a pair of huge brass doors on the second level of the keep. You see no means of entry to the first level.
A single tower adorned with serpentine waterspouts is connected to the central keep by a diagonal arm of stone. It juts upward, blocking part of your view of the cliff face above the hollow. Two wider towers hang down from the top of the hollow like fangs in a great stone mouth.
A single tower adorned with serpentine waterspouts is connected to the central keep by a diagonal arm of stone. It juts upward, blocking part of your view of the cliff face above the hollow. Two wider towers hang down from the top of the hollow like fangs in a great stone mouth.
Although any observer can tell that the castle’s construction is odd, a successful DC 15 Knowledge (architecture and engineering) check confi rms that the fortress exhibits traits of yuan-ti construction.
The keep makes up the bulk of Castle Serastis, though it contains none of the locations most important to the Vanguard.
K1. THE SERPENTS’ STAIR
The Cult expected Lieth to serve as sentry as well as taskmaster, so the entrance to the castle is unguarded. Gaining access to the interior is not easy, however.When the PCs climb the stairs, read:
Read aloudThe massive brass doors are set roughly 10 feet into the fortress, creating a small foyer—or perhaps a kill zone—between the stairs and the entry.
If Lieth succeeded in fleeing to the fortress after the encounter in area F, read:
Read aloudA brass portcullis at the top of the steps prevents access to the doors.
If Lieth was kept from reaching the fortress, read:Read aloudAbove the highest step, recessed into the ceiling, you can see where a great brass portcullis is currently raised.
The door (area K2) and the portcullis (if down) are formidable obstacles. Both are solid iron gilded with brass.
Iron Portcullis: 2 inches thick; hardness 10, hp 30, break DC 28; Strength DC 25 to lift.
CR 1; mechanical; location trigger; manual reset; Atk melee (); Search DC 22 (to fi nd the mechanism; the portcullis is obvious); Disable Device DC 20.
The damage applies only to creatures underneath the portcullis if it drops. Such creatures are knocked prone and held in place until the portcullis is lifted or they succeed on a DC 20 Escape Artist check.
If it is not already down, the portcullis might be triggered by the PCs’ actions in area K2.
K2. THE MOUTH OF SERASTIS
The portcullis and the door can be opened only from the inside (see K3).When the PCs approach the doors, read:
Read aloudAs you approach the double doors, their detail becomes visible in the shadows. Both brass portals are covered in hideous engravings of demonic serpentine figures.
Barred Iron Door: 2 inches thick; hardness 10, hp 60, break DC 38.
The doors are held shut by a system of winches and counterweights, and must be disabled or forced. A successful DC 22 Search check reveals a few thin openings around the door frame that allow access to the cables. A successful DC 22 Disable Device check causes the counterweights to release and the doors to creak slowly open.
The counterweight system is tricky. If the first Disable Device check fails by 5 or more, the portcullis in area K1 drops with a loud crash, potentially trapping PCs in the kill zone. Roll for random encounters as though the trapped PCs were inside the fortress. Any patrol appears from the base of the stairs and fi res at the PCs through the bars.
If all else fails, the PCs can wait until someone opens the door from the inside. If this occurs, they encounter a patrol of four yuan-ti purebloods (this counts as one of the eight pureblood patrols that can be encountered). Unfortunately, patrols depart by the main door only every hours.
K3. THE GREAT HALL
The massive foyer of Castle Serastis is built to impress.When the PCs enter, read:
Read aloudThe enormous hall you fi nd yourself in is as large as a castle keep. Much of the chamber is open to the level above, allowing anyone on the fl oor above to look down upon it. Two large winches, their handles carved to resemble striking cobras, fl ank the double door. Across the chamber, clear water glints within a circular marble pool, but your gaze is drawn beyond it to a massive reptilian skeleton at the back of the hall.
The winches control access to the central keep. The south winch opens and closes the great door (K2), while the north winch raises and lowers the portcullis (K1).
A shallow stair (barely more than a ramp) curves upward and around from the south side of the room, eventually leading to area K15.
Give the PCs time to take in the room from the doorway if they have been cautious enough to advance unseen. However, any character who enters the hall triggers the tactical encounter.
Tactical Encounter: K3. The Great Hall, page 30. The battle with Prath and the guardian makes substantial noise. As long as the PCs remain in this area, check for random encounters every 5 minutes. (If the party leaves this area and returns more than 1 hour later, random encounters revert to normal.)
Random Encounters: Roll for a random encounter in area K15 any time the PCs pass through area K3. If an encounter occurs, the guards in K15 snipe from above. Characters adjacent to the railing in K15 have line of sight to anyone below, as described in area K15 (page 15).
Treasure: In addition to Prath’s possessions (see the tactical encounter), anyone examining the pool sees a 12-inch-wide silver inlay at the bottom in the shape of a coiled serpent. A successful DC 22 Search check notes chipped stone around it, revealing that it can be pried off (a DC 15 Strength check). The silver icon is worth 1,500 gp.
K4. DINING HALL
The cult’s minions take their meals in this area.Illumination: Continual fl ame wall sconces shed bright light throughout this area.
When the PCs enter, read:
Read aloudThis lengthy chamber boasts a pair of heavy wooden tables and a number of rough chairs. Dried bloodstains on the wood give a hint to the nature of the foul repasts consumed here.
The secret door leads to a sloping and winding passageway that connects to the barracks (K16A). A small grate in the fl oor (Spot DC 10) allows spilled liquids and detritus to be swept down into a series of pipes leading to the garbage pit (K11). The pipes are too small for anything larger than a rat to pass through.Random Encounters: Any random encounter here is with a human or yuan-ti patrol on dinner break. Its members are gathered at a table, though one has a 20% chance of being found in the kitchen (K5). This character appears in 2 rounds if combat breaks out.
The abominations do not eat here. If a group with an abomination is indicated, reroll.
Tables and Chairs: Squares occupied by tables or chairs are considered difficult terrain, and tables provide cover to adjacent characters. A character can step up onto a table as a move action, gaining a +1 bonus on melee attack rolls against those on the floor. Two characters working together can tip over a table to provide cover against ranged attacks.
K5. KITCHEN
Though this kitchen is small relative to the size of the castle, only the castle’s humanoids use it for cooking. The yuan-ti prefer their meat raw—most often beef, but occasionally slaves from the valley that are eaten alive.Illumination: Continual flame wall sconces shed bright light throughout this area.
When the PCs look in, read:
Read aloudThis rough kitchen is dominated by a stone table, its surface marred by deep gouges and bloodstains. Pungent slabs of beef are stacked in the southwest corner. A few dim embers glow in a fi repit to the northeast. A blackened humanoid skull lies shattered in the ashes.
No random encounters occur in this room except as noted in area K4. A small grate in the fl oor (Spot DC 10) serves the same purpose as the grate in the dining room.
Treasure: Hanging on hooks next to the slabs of meat are a half-dozen oversized knives and cleavers. Though they appear nondescript, they are sturdy enough to serve as improvised weapons (treat as daggers and handaxes).
K6. TORTURE CHAMBER The doors of this room are locked.
Illumination: Continual flame wall sconces shed bright light throughout this area.
When the PCs open the doors, read:
Read aloudBeyond the doors lies a true chamber of horrors. A rack and an iron maiden stand next to terrible contraptions of cables, needles, and cuffs whose purpose is best not guessed at. The floor is stained with dried blood, a red-black pool spreading around a rusty iron grate in the center of the floor.
The builders of Castle Serastis placed the torture chamber on the level above the cells, so that the castle’s masters would not have to enter the dungeons for interrogations or entertainment. The iron grate allows spilled blood to fl ow into the same series of pipes as those found in K4 and K5. A shallow stair in the north side of the room leads to the cells below (K9).
Random Encounters: The fi rst random encounter occurring here involves the torture of a prisoner (Rollin, from cell K10C). His tormentors want no information from him; they are merely amusing themselves. If rescued, Rollin tells the PCs of the other prisoners below, warns them of Yensurros (see K9), and can offer any of the information described in K10.
Any random encounters here after the PCs free the prisoners from the dungeon involve patrols simply passing through the area.
Torture Devices: Squares occupied by torture devices are considered difficult terrain and provide cover to adjacent characters. Anyone bull rushed or otherwise knocked into a torture device takes points of additional damage from its spikes,blades, or other external trappings. K6A. Temporary Cells: The locked doors to these cells feature small barred windows.
If the PCs look within, read:
Read aloudThese small rooms contain nothing but piles of moldy straw.
Prisoners awaiting torture are moved from the cells below into these holding pens. The yuan-ti believe (correctly) that hearing the screams of those who go before them weakens the prisoners’ will before interrogation even begins.
K7. MEETING HALL
The door between this chamber and K6 is locked; the others are not.When the PCs enter, read:
Read aloudThis large open chamber appears to be an audience hall. A raised dais sits against the east wall, complete with a stone podium adorned with serpentine carvings.
Once one of the most vital areas of Castle Serastis, the meeting hall has seen little use in the past few months. The Cult's servants know their assignments, and any councils now take place in the castle’s shrines.
The secret door opens onto a twisting passage. This slopes down to the passage outside K13 and up to the passage connecting the barracks (K16).
Hidden Pit Trap: CR 3; mechanical; location trigger; manual reset; DC 20 Reflex save avoids; 30 feet deep (, fall); multiple targets (fi rst target in each of two adjacent squares); Search DC 24; Disable Device DC 18. Characters falling into this pit end up in cell K10F.
This pit is activated by a hidden switch on the lectern (Search DC 24), and was used to publicly punish cultists whose faith was found lacking. Though the trap has not been used in some time, the patrols know to avoid it. The trap is triggered by 40 pounds or more of pressure, but anyone who searches the podium and fi nds the switch can deactivate it (no Disable Device check needed).
Dais: Characters on the dais gain a +1 bonus on melee attack rolls against those on the floor or a lower step
K8. THE LESSER SHRINE
The faithful of Sertrous use this shrine for brief prayers and ceremonies when they have no time to travel to the Tower of Worship.When the PCs look in, read:
Read aloudThe walls of this rectangular chamber are covered in carvings. What first seems a group of serpentine fi gures reveals itself to be a single, impossibly long snake with numerous heads along the length of its body. Near the west wall stands an altar slab of black marble atop an iron stand in the form of a coiled cobra.
Standing beside the altar is a tall, broad-shouldered lizardfolk clad in green leather. His dusky scales are almost black, and he stares at you with unblinking eyes. However, though his clawed talons clench the hilt of a spear, he makes no move to attack.
Chavakuth was a druid of the Dark Talon tribe (MM4 83) before becoming a faithful servant and worshiper of Sertrous. For all his zealotry, however, he has never lost his seething hatred of other lizardfolk tribes—particularly the poison dusks that have taken up a position of prominence within the castle guard. He is willing to cooperate with the PCs if it means striking at those ancestral rivals. If the PCs do not attack, a DC 18 Diplomacy check engages Chavakuth in conversation. (Characters speaking Draconic gain a +3 circumstance bonus on the check.) If the PCs fail the Diplomacy check, make any overtly hostile move, or demand more aid than Chavakuth is willing to give, they trigger the tactical encounter.Standing beside the altar is a tall, broad-shouldered lizardfolk clad in green leather. His dusky scales are almost black, and he stares at you with unblinking eyes. However, though his clawed talons clench the hilt of a spear, he makes no move to attack.
Tactical Encounter: K8. The Lesser Shrine, page 31.
Diplomacy: If the PCs speak to Chavakuth, he reveals the following information as part of a careful and tentative backand-forth. Read the following in response to player questions, extrapolating as appropriate. (Chavakuth’s halting speech results from his speaking Common only infrequently. If one of the PCs speaks Abyssal, Draconic, or Druidic, alter it accordingly.)
- “I am Chavakuth. I am shaman of Dark Talon tribe. I serve the Sertrous, master of all.”
- “All Vanguard readies for the Sertrous to awaken. His sacrament nearly complete.”
- “You cannot defeat the Sertrous or his Vanguard. No mortal can. But maybe you survive to fl ee. Maybe I help you survive, yes? And you help me back, yes?”
- “Tiny poison dusk tribe also worship the Sertrous. They dirty his Vanguard with being here. I tell you where to find poison dusk, you kill. Vanguard purifi ed, and I help you survive. Yes?”
Though Chavakuth hates the poison dusk lizardfolk and is willing to aid the PCs against them, he will not turn traitor against the Vanguard as a whole. Any attempt to make him do so results in violence.
If the PCs agree to his bargain, Chavakuth gives them specific directions to the poison dusk guards in the passage (K18) to the Tower of the Way. He also directs them to one of the wandering poison dusk patrols (so that the next random encounter is with a poison dusk group).
The PCs can obtain additional aid from Chavakuth, but only after bringing back proof of having slain at least one group of poison dusks and promising to slay another. If one of the party is injured in the fi rst raid, the druid offers his potion of cure moderate wounds as a boon for the PCs’ service. If pressed for greater assistance, he agrees to let the characters rest in the shrine for one night. Additionally, if the PCs succeed on a DC 23 Diplomacy check (again with a +3 circumstance bonus for speaking Draconic), he reluctantly tells them of the prisoners in the cells below (K9 and K10), showing them the secret door in the south wall of the shrine.
Allowing the prisoners to escape is the closest Chavakuth comes to betraying the Vanguard. He refuses any requests beyond that, and attacks if the PCs attempt to force the issue.
The passage behind the secret door slopes downward, providing access to K13 and to a hidden exit from the fortress.
Ad Hoc XP Award: If the PCs deal with the encounter diplomatically from beginning to end, award them XP as if they had successfully overcome a CR 6 encounter.