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Clockwork Gatekeeper - AI-generated fantasy Hazard

Clockwork Gatekeeper

The Clockwork Gatekeeper is a dormant guardian installed in a ruined observatory. It interprets nearby movement and sound as an attempt to breach the sealed chamber, then releases precise bursts of force while its brass arms lash at intruders. The mechanism is dangerous, but its patterns are regular enough for observant adventurers to exploit.

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Hazard EntryGuardianLevel4Simple

Clockwork Gatekeeper

4LevelUncommonRarityRuinsEnvironment
MechanicalMagicalGuardianAudibleFixed Position
Level4
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HP30
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AC15
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TypeGuardian
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ComplexitySimple
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RarityUncommon

Defenses

AC15
HardNot applicable in D&D 5E. Treat the mechanism as an object with AC 15 and the listed hit points.
HP30
BT A creature that succeeds on the initial saving throw, or a creature that uses an action to jam the central gear with a suitable object, ends the hazard's active cycle. The barrier remains sealed until the mechanism is disabled or bypassed.
Fort+Not applicable in D&D 5E. The mechanism has immunity to poison and psychic damage.
Ref+Not applicable in D&D 5E. Its main area effect calls for a Dexterity saving throw.
Will+Not applicable in D&D 5E. The guardian is immune to effects that require a creature to be charmed or frightened.
Immune
Poison damage, Psychic damage, Poisoned condition, Charmed condition, Frightened condition, Exhaustion
Resist
Bludgeoning, piercing, and slashing damage from nonmagical attacks, at the DM's discretion if the mechanism is treated as a reinforced object
Weak
A properly tuned brass token from the observatory grants advantage on checks made to bypass or disable the guardian., Lightning damage causes the guardian to seize until the end of its next turn. It cannot use Brass Arm Strike during that time., A creature that remains completely motionless for one full round is ignored by the guardian until it moves or speaks.
MechanicalMagicalGuardianAudibleFixed Position

Detection

PerDC 13 Wisdom (Perception) to notice before activation. Once active, its ticking and grinding are obvious.
StlDC 12 Dexterity (Stealth) to approach without disturbing the mechanism. The check is made with disadvantage if a creature is wearing metal armor or carrying loose metal objects.
InitThe guardian activates on initiative count 20 immediately after it is triggered. It then acts on initiative count 20 each round until disabled or bypassed.

“A waist-high brass plinth stands before a sealed ruin entrance. Its face bears a tarnished clock dial with no hands, while three thin metal arms rest against the surrounding stone like folded spider legs. Tiny gears turn behind cracked glass whenever nearby creatures speak.”

Standard Engagement

Trigger

The guardian activates when a creature touches the sealed entrance, steps within 5 feet of the plinth, or creates a sharp sound such as shouting, striking metal, or casting a spell with a verbal component within 20 feet.

Routine

On initiative count 20, the guardian releases one Resonant Time Pulse, then makes one Brass Arm Strike against the nearest creature within 10 feet. If no creature is within range, it makes no attack that round.

Reset

After 10 minutes without detecting movement, sound, or contact with the sealed entrance, the guardian returns to its dormant state. If disabled by locking its gears or damaging its mechanism, it does not reset until repaired.

Resonant Time Pulse

When the guardian activates, each creature within 15 feet of the plinth must make a DC 14 Dexterity saving throw. On a failure, the creature takes 7 (2d6) force damage and is pushed up to 10 feet away from the plinth. On a success, it takes half damage and is not pushed.

Brass Arm Strike

The guardian makes one mechanical arm attack against the nearest creature within 10 feet. The attack bonus is +5. On a hit, the target takes 6 (1d8 + 2) bludgeoning damage and must succeed on a DC 13 Strength saving throw or fall prone.

Indiscriminate Mechanism

The guardian's pulse does not distinguish friend from foe. It affects all creatures in the area, including creatures that triggered it.

Predictable Rhythm

The guardian's attacks follow a predictable rhythm. After observing one full round, a creature can use a bonus action to call out the timing. Until the start of that creature's next turn, allies within 15 feet of it have advantage on saving throws against Resonant Time Pulse.

Fixed Sentinel

The guardian cannot pursue creatures more than 10 feet from the plinth. Its arms retract, but the pulse still affects creatures within 15 feet.

Description

The Clockwork Gatekeeper is a dormant guardian installed in a ruined observatory. It interprets nearby movement and sound as an attempt to breach the sealed chamber, then releases precise bursts of force while its brass arms lash at intruders. The mechanism is dangerous, but its patterns are regular enough for observant adventurers to exploit.

Discovery

The guardian can be noticed before it activates with a DC 13 Wisdom (Perception) check. A successful check reveals the articulated arms, fresh scoring on the floor, and a faint ticking beneath the stone. A character who examines the murals and succeeds on a DC 13 Intelligence (Investigation) check notices that their astronomical symbols correspond to the guardian's dial.

Archival Lore

“The observatory once regulated the calendars, tides, and ceremonial entrances of a clockwork-focused priesthood. The gatekeeper was designed to protect a chamber containing an artificial star, but centuries without maintenance have made its recognition protocols overly aggressive.”

Environment
Ruins
Theme
Clockwork
Creator
The vanished horologist-priests of Veyr
Purpose
To prevent unauthorized entry into the observatory's sealed inner chamber.
Game System
D&D 5E
Art Style
Dark fantasy concept art, ruined temple machinery, corroded brass, blue-white arcane sparks, dramatic torchlight, intricate mechanical details
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