Large
Construct
CR 12
Unaligned
Tenebric Bastion
Ancient Construct Sentinel
A hulking lattice of dark bronze plates, glassy lenses, and rusted sigils, the Tenebric Bastion lumbers from its burial niche with the inevitability of a long-buried law. It moves with surprising deliberation for its bulk; each step is accompanied by a grinding of old gears and a faint whisper of lost commands. When roused it does not seek blood for pleasure but fulfilment of purpose — any who defile the barrow or attempt to remove the relics it guards will be met by an implacable, tactical force that can lash out with proportionate brutality and crash magical defenses with an ancient pulse of stored war-magic.
Armour
18
layered bronze plating and warding sigils
Hit points
241
23d10+115
Speed
30ft
Challenge
12
8,400 XP
STR
20
+5
DEX
12
+1
CON
20
+5
INT
14
+2
WIS
14
+2
CHA
10
+0
Saving throws
STR +9, CON +9, INT +6
Skills
Perception +6, Investigation +6
Resistances
bludgeoning, piercing, and slashing from nonmagical attacks
Damage immunities
poison, psychic
Condition immunities
charmed, exhaustion, poisoned
Senses
darkvision 60 ft., passive Perception 16
Languages
understands Common but can't speak
Multiattack. The Tenebric Bastion makes three Slam attacks.
Slam. Melee Weapon Attack: +9 to hit, reach 10 ft., one target. Hit: 16 (2d10+5) bludgeoning damage. If the target is a creature, it must succeed on a DC 14 Strength saving throw or be knocked prone.
Arc Pulse (Recharge 5-6). The Bastion releases a rupturing pulse of stored war-magic in a 30-foot cone. Each creature in that area must make a DC 14 Dexterity saving throw, taking 27 (6d8) lightning damage on a failed save, or half as much on a successful one. A creature that fails the save by 5 or more is also stunned until the end of the Bastion's next turn as circuits and wards briefly overload.
Grav-Tether. Ranged Weapon Attack: +9 to hit, range 30/90 ft., one target. Hit: 14 (2d8+5) bludgeoning damage, and the target is pulled up to 10 feet closer to the Bastion if it is Large or smaller and fails a DC 14 Strength saving throw.
Servo Shield. When a creature the Bastion can see within 10 feet is hit by an attack, the Bastion can use its reaction to interpose a plated arm. The attack targets the Bastion instead and the Bastion adds +2 to its AC against that attack. If the attack misses because of this reaction, the attacker is pushed 5 feet away from the Bastion.
Forged by the vault-smiths of House Mavraen nearly seven centuries ago, the Tenebric Bastion was not a simple automaton but a fielded law — a walking garrison installed to watch the family crypts of the barrow-halls outside Kharvoss. House Mavraen imbued each Bastion with a fragment of a litany called the Covenant of Watch, a ritual of will that anchors the construct's waking and its rules of engagement. Over time the Bastion was interred when the family was betrayed and the vault sealed; the litany's final clause caused the machine to enter an extended dormant state rather than rot in place. Scholars of antiquities, such as Archivist Madir of the Collegium of Sundering, have theorized that the Bastion's war-magic can draw power from both the dead it guards and the ley-lines that pass under many barrows. Bands of grave-robbers learned to fear single Bastions after a string of raids ended with the raiders' hands and not their loot returned. The barrow where your party awoke this Bastion is rumored by locals to be a death-trap called the Hollow of Kervan, and the folk-singers avoid the road after dusk. The Collegium keeps a locked report labeled 'Bastion-class constructs — recovery & pacification protocols' for a reason: pacifying a Tenebric Bastion is possible, but costly and ritual-laden.
Imagine a towering, humanoid machine roughly the height of a large doorway (about 9 feet tall) and built of overlapping bronze plates darkened with verdigris and soot. Its torso is a ribbed cage of filigreed metal that hides a dimly pulsing core pod, veined with brittle glass tubes. Limbs are thick segmented pistons, each joint bolted with oversized rivets and wrapped with braided copper filaments that hum faintly when the construct moves. Its head is a faceted hemispherical helm with three glazed lenses in a vertical row: the central lens is the largest and emits a low inner light when awake. Old ward-runes, some pitted by time and others glowing faintly, are etched across its chest and the inside of its forearms. The fingers end in blunt, drupe-shaped hammers and small auxiliary tools (a pry-claw and a jeweler's pick) that can retract from beneath armored plates. Surface textures vary: corroded hammered metal, smooth polished bronze in places where hands rested for centuries, and strips of woven leather used in antiquity to insulate arc conduits. A human stands about to its mid-thigh, giving a clear scale for artists.
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