The demon lord Xar’Thagus stirs in the chaotic evil planes, and the Cult of the Black Wyrm races to reassemble the shattered Eye that will tear open the barriers between worlds — only the heroes of Drakenheart stand in their way.
Welcome to “Chains of the Fiend” 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.
“Chains of the Fiend” is a direct sequel to “Wings of Dread.” In a party of 4-6 characters (levels 9-11), the heroes return to a recovering Drakenheart to find the Obsidian Shard — a relic taken from Nyrathalor’s hoard — pulsing with dark energy. Court wizard Magister Elenora reveals it is a fragment of the Eye of Xar’Thagus, an artifact that can tear open the boundaries between the Material Plane and the chaotic evil planes. The Cult of the Black Wyrm, thought destroyed, has returned with a singular goal: reassemble the Eye and summon Xar’Thagus the Deceiver into the world. The adventure spans four parts, culminating in a journey into the fiend’s own realm.
Part 1: Trouble in Drakenheart
Six months after Nyrathalor’s fall, the characters return to a city still rebuilding — but plagued by unnatural storms, fiendish creature sightings, and citizens suffering vivid nightmares. King Alden V summons the party and introduces Magister Elenora, who has been studying the Obsidian Shard and now fears its rapidly growing power. At her tower, the Sage’s Sanctum, she performs a protection ritual, explains the Eye of Xar’Thagus, and directs the heroes to their first destination: the Obsidian Archive, an ancient elven repository hidden in the ruins of Aethoria, where the secrets of the Eye — and how to stop it — may be found.
Part 2: Gathering the Pieces
The heart of the adventure sends the party to three increasingly dangerous locations to recover all three fragments of the Eye before the cult can use them.
At the Obsidian Archive in the ruins of Aethoria, a one-day journey through magically warped wilderness, the party must disable powerful elven wards to enter, then navigate a self-rearranging Labyrinth of Knowledge guarded by animated elven sentinels. A Riddle Chamber tests their knowledge of Xar’Thagus through three questions answered to an ancient elven sage projection, and a final Vault of Forbidden Lore — guarded by an Arcane Sentinel — holds a crucial tome revealing the Eye’s history, the demon lord’s true name, and the location of the second fragment.
The Desecrated Cathedral, buried in Drakenheart’s abandoned Shadowmire District, offers three entry points — the fiend-warded front doors, a shattered stained-glass window, or a disease-riddled sewer passage. Inside, the party deactivates unholy sigils in the corrupted nave (each failure summoning Shadows), solves a symbol-alignment puzzle to open the altar hiding the second Eye fragment, and descends into crypts where a Bone Devil leads a ritual that must be stopped within five rounds or be empowered by completion.
The Tower of Eyes, a reality-warping structure on Drakenheart’s outskirts, is the cult’s final stronghold. A Vestibule of Distortion with shifting geometry separates and slams party members while Glabrezu and Shadow Demons attack. A Spiral Staircase of Shifting Realities forces Wisdom saves against madness with each ascent. A Chamber of Reflections demands the party identify the true mirror among dozens of distorted reflections — each failure unleashing a fiendish duplicate of a party member. At the summit, the Eye Tyrant guards the final fragment in the All-Seeing Chamber.
Part 3: Journey Through the Chaotic Evil Planes
With the Eye fully assembled, the party performs the ritual to open a portal and plunge into Xar’Thagus’s realm — a nightmarish landscape where exhaustion builds with every rest, wild magic surges threaten every spell, and visions of their worst fears appear without warning. They must cross the River of Blood (by raft, magic, or a hidden bone bridge), navigate the Nightmare Labyrinth whose walls manifest Shadows of Fear drawn from each character’s personal traumas, and battle Pit Lord Kaz’goroth at the Spawning Pits as lesser demons crawl from the mire. A final stretch known as the Corruption of the Eye strips away the characters’ faculties across three escalating levels of corruption — clouded eyes, unnatural skin, and maddening whispers — before the gates of Xar’Thagus’s fortress rise before them.
Part 4: Xar’Thagus’s Fortress
A citadel of bone, iron, and lost souls where reality warps constantly, darkvision is halved, and rest offers no respite from the fortress’s draining aura. The party solves a fiendish gear-and-bone puzzle at the Gates of Bone — or fights through a Bone Devil and Barbed Devils that answer the alarm. The Hall of Whispers forces Wisdom saves against charm, fear, and exhaustion, culminating in an ambush by Xar’Thagus’s lieutenants. In the Chamber of Lost Souls, the Soulbound — a fusion of countless tormented spirits — can be defeated in combat or unbound through careful use of the Eye itself. The final battle in the Throne of Lies pits the party against Xar’Thagus across three phases: a Fiendish Colossus form relying on brute force and splitting into multiple targets, a Deceiver’s Shadow form that warps and reshifts the battlefield at half health, and a desperate final stand calling forth additional fiends and threatening to trap the party in his realm forever. When he falls, the fortress collapses, demanding a frantic escape through crumbling hallways and dimensional tears before the chaotic evil planes swallow everything.
Back in the Material Plane, the party faces the adventure’s defining choice: destroy the Eye and seal the threat forever, safeguard it in secret and shoulder the burden of its existence, or wield it — gaining immense power while the Eye’s corruption slowly erodes their soul and edges them toward becoming the next fiendish threat to the world.
Release Date: 2024
Format: Digital (PDF)
Items Included
- Chains of the Fiend 5E (PDF)
- A B&W Printer-Friendly Version (PDF)
- Maps
- Illustrations (Generated with Midjourney)
- Monster Stat Blocks
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