A cleric whose faith shattered when his family died of plague has retreated to a cursed abandoned castle, raised an army of the dead, forged a pact with a demon lord, and now plans to open a portal to the Abyss during a lunar eclipse — unless the party can reach him in time.
Welcome to “The Fallen Cleric” 5E adventure! Within these pages, you’ll discover everything necessary to embark on this thrilling quest, complete with detailed descriptions of locations, encounters, NPCs and stat blocks, maps, and handouts.
This adventure also features a versatile and scalable system, allowing Game Masters to easily adjust the difficulty and complexity of encounters to suit their players’ preferences and skill levels. Whether you have a party of advanced players or beginners, you can tailor the challenges to ensure an exciting and engaging experience for everyone involved. The scalable system guides modifying creature statistics, making it simple to customize the adventure to fit your party’s level.
In “The Fallen Cleric,” a party of 4-6 characters (levels 5-7) is hired by Thorvald Blackmere, a wealthy landowner in the town of Lakeshore, after he receives a frantic letter from his scholar friend Caelum Lorekeep warning of “unholy rites” and “walking corpses” at the abandoned Castle Morose. The castle’s last noble family, the Moroses, were wiped out by plague decades ago — and Valen Morose, a distant descendant and once-respected cleric of the Church of Light, lost his own wife and child to the same disease. Excommunicated after turning to forbidden necromancy in his grief, Valen now commands the castle’s dead, hosts the barbed devil Malgrath as his lieutenant, and prepares a grand ritual to summon a demon lord during that very night’s lunar eclipse. Caelum, captured while investigating the ruins, is being held as the ritual’s final component — a “true believer’s heart, freely given.” The party has 500 gp per character waiting on their return and one night to act. The adventure is divided into three parts.
Part 1: Beginning the Adventure
In Lakeshore, Thorvald meets the party at the Silver Trout tavern and shares Caelum’s letter — written in frantic haste and describing “a fallen servant of light” speaking of “opening the way” before Caelum was discovered and fled. Thorvald provides horses, a week’s provisions, a castle map, and a letter of introduction bearing his seal. Information-gathering in town yields Castle Morose’s history (plague-wiped noble family, abandoned for thirty years), Valen’s identity (an excommunicated cleric whose heretical necromancy studies were discovered by the Church of Light), and rumor from locals of missing farmhands and strange lights on the horizon.
Part 2: Journey to the Castle
The three-day ride east tracks the deterioration of civilization into desolation. On Day One, the party passes abandoned farmsteads; one holds drag marks suggesting people were taken unconscious, a hidden lockbox with a Church of Light warning letter, and 25 gp in coin. On Day Two, they encounter merchant caravan leader Dorna Blackwell, who abandoned her planned route due to reports of walking corpses attacking a prior caravan and strange lights two nights ago. Dorna offers a 20% supply discount to bearers of Thorvald’s seal. On Day Three, unnatural fog drops visibility to 60 feet, wildlife vanishes entirely, and a group of corrupted bandits — pale, dark-veined, driven toward Valen in exchange for promised safety — ambush the party from the mist. Their leader carries a Withered Human Eye in a talisman pouch that serves as the key to Castle Morose’s puzzle gate. Captured bandits reveal the eclipse begins tonight, the castle is defended by walking dead and demons, and the gate requires “the word and the key.”
Part 3: The Abandoned Castle
Castle Morose offers three alternative entry points — a collapsed western wall (DC 15 Athletics), a drainage tunnel (DC 14 Acrobatics), and a crumbling southern tower (DC 16 Athletics) — but all trigger necromantic glyph alarms within 30 feet of the walls, awakening four skeleton battlement sentries regardless. Seven mapped areas span the fortress.
The Castle Gate bears a magical puzzle lock: the Withered Eye placed in a rune receptacle triggers a riddle in Common (“I see all but am blind, I speak truth but have no mouth, I live forever but am already dead” — answer: history). Wrong answers destroy the eye and deal 3d6 fire damage in a 10-foot burst. The Courtyard, under an active Unhallow spell granting undead advantage on turn-undead saves, is patrolled by eight zombies and four skeletons; a hidden trapdoor near the western wall (DC 16 Perception) leads to a tunnel connecting to the dungeon level.
In the Great Hall, Valen’s lieutenant Malgrath — a barbed devil — lounges on the black-stone throne and attempts a parley before summoning two hell hounds. The throne conceals 150 gp, a potion of greater healing, and a small iron key that unlocks the chapel’s hidden passage; a separate mechanism on the throne’s armrest (DC 15 Perception or Investigation) reveals a spiral staircase descending directly to the Summoning Chamber. The Castle Wings hold three captive commoners in kitchen cages who confirm the ritual deadline is the eclipse, plus dormant zombies and skeletons in the former barracks. The dungeon level hides a potion of invisibility and crude castle map in a loose cell-wall stone (DC 15 Perception), and a courtyard-connecting secret tunnel in the northernmost cell.
The Chapel — pews overturned, windows blackened, chains bearing desiccated sacrificial remains — is guarded by two wights. A trapped central aisle (DC 15 Perception to spot) drops characters into a spiked 10-foot pit (2d6 bludgeoning + 2d10 piercing). The desecrated altar radiates death magic and burns with green flame (4d6 necrotic on touch, DC 15 Constitution for half). Behind it, a locked secret stone door (DC 14 Perception; opened by Malgrath’s key or DC 15 thieves’ tools) leads to a passage splitting toward both the laboratory and the Summoning Chamber.
Valen’s Laboratory holds the fallen cleric himself alongside a flesh golem and two cult fanatics. Valen monologues about the Church’s betrayal and his vision of a cleansed world before the fight — his research notes (DC 15 Investigation) confirm the eclipse timing, the Abyss portal goal, and that Caelum is the ritual’s final component. Treasure includes a scroll of Revivify, a potion of superior healing, 300 gp in components, and a spellbook of necromantic spells. A second hidden passage (DC 16 Perception) connects the laboratory directly to the Summoning Chamber.
The Summoning Chamber at the top of the central tower has had its ceiling removed to expose the eclipsing moon. A liquid-silver summoning circle pulses at the center, ringed by five skull-topped pillars glowing red. Caelum Lorekeep is chained to the wall, painted with arcane symbols, barely conscious. If Valen was already defeated, a Bone Devil has been left to complete the ritual in his place. The ritual — sacrificing Caelum at eclipse peak to open a Glabrezu portal — can be disrupted by defeating Valen or the Bone Devil, freeing Caelum beforehand, or destroying the five skull pillars (AC 15, 20 HP each, triggering 6d6 force damage DC 15 Dex save on destruction).
Three outcomes close the adventure: Full success — Valen defeated, Caelum rescued, ritual stopped — disperses the dark magic, silences the undead, and earns 500 gp per character from Thorvald plus Valen’s unholy symbol, a ring of protection, and a chest containing 500 gp and three 100 gp gems. Partial success — ritual stopped but Valen escaped, or Valen dead but the Bone Devil nearly completes the ritual — averts the immediate threat but leaves open hooks for Valen’s return or lingering demonic corruption. Failure brings the demon lord through the portal, sends Valen to his knees in triumph, and launches a catastrophic campaign arc against the forces now spilling into the world.
Release Date: 2025
Format: Digital (PDF)
Items Included
- The Fallen Cleric 5E (PDF)
- A B&W Printer-Friendly Version (PDF)
- Maps
- Illustrations (Generated with Midjourney)
- Monster Stat Blocks
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