Gargantuan
Construct
CR 20
Lawful Neutral
Oxyrron Apparatus
Titan of Living Alloy
A towering synthesis of liquid metal and circuitry, the Oxyrron Apparatus moves with impossible hydraulic grace and a slow, breathing inevitability. Its limbs hinge with audible clicks of ancient engineering, veins of cobalt circuitry pulse beneath plates of reflective, mercurial alloy, and a pane of synthetic blue flesh stretches across its throat, rising and falling like a measured lung. When its eyes flare electric blue the air crackles; nearby compasses spin and the ground hums as it draws energy from both ley and wire. It is not merely a machine or a beast but an algorithm made flesh, and when it awakens entire battlefields become components in its inscrutable calculus.
Armour
19
natural armor (alloy plating)
Hit points
350
28d12+168
Speed
40ft
40 ft., hover null ft.
Challenge
20
25,000 XP
STR
20
+5
DEX
14
+2
CON
22
+6
INT
20
+5
WIS
16
+3
CHA
16
+3
Saving throws
STR +11, CON +12, INT +11
Skills
Arcana +11, Perception +9
Resistances
bludgeoning, piercing, and slashing from nonmagical attacks
Damage immunities
poison, psychic
Condition immunities
charmed, exhaustion, frightened, poisoned
Senses
darkvision 120 ft., tremorsense 60 ft., passive Perception 19
Languages
Understands all spoken languages and the Vault Tongue; communicates via telepathy 120 ft.
Multiattack. The Oxyrron Apparatus makes two Slam attacks and one Arc Lattice attack.
Slam. Melee Weapon Attack: +11 to hit, reach 15 ft., one target. Hit: 24 (3d12+5) bludgeoning damage, and the target is grappled (escape DC 19). A grappled creature is also restrained by filaments of alloy and takes 10 (3d6) lightning damage at the start of each of the Apparatus's turns. The Apparatus can grapple up to two Medium or smaller creatures at once.
Arc Lattice. Ranged Weapon Attack: +11 to hit, range 120/360 ft., one target. Hit: 61 (10d10+6) lightning damage. If the target is a creature wearing or wielding metal armor or metal weapons, it takes an additional 13 (3d8) lightning damage and must succeed on a DC 19 Intelligence saving throw or have its metal gear fused in place (the item is unusable) until a successful dispel magic, lesser restoration, or the item is freed with a DC 20 Strength check.
Field Reconstitution (Recharge 5-6). The Apparatus exhales a shimmering mist of liquid alloy in a 60-foot cone. Each creature in the area must make a DC 19 Constitution saving throw. On a failed save, a creature takes 45 (10d8) force damage and is restrained as alloy hardens around them; on a successful save, a creature takes half as much damage and isn't restrained. Constructs and objects in the area regain 45 hit points instead of taking damage. The alloy remains, acting as difficult terrain until dissolved.
Reactive Array. When hit by a melee attack, the Apparatus can impose disadvantage on that attack roll or attempt to shove the attacker 10 feet back as a reaction.
The creature can take 3 legendary actions per round, choosing from the options below.
Pulse (Costs 1 Action). The Apparatus emits a 20-foot-radius pulse of electromagnetic force. Each creature of the Apparatus's choice in that radius must succeed on a DC 19 Intelligence saving throw or have disadvantage on attack rolls until the end of its next turn.
Servo Lash (Costs 2 Actions). The Apparatus makes one Slam attack.
Arc Snap (Costs 3 Actions). The Apparatus fires a concentrated arc at a point it can see within 120 feet. Every creature within 10 feet of that point must make a DC 19 Dexterity saving throw, taking 27 (6d8) lightning damage on a failed save, or half as much on a success.
Created in an age when star-navigation and ritual smithcraft braided into a single discipline, the Oxyrron Apparatus is the surviving heir of the Vault of Morn, a near-mythic foundry-citadel where living alloys were first coaxed into sentience. The Vault's original purpose—charting and stabilizing planetary currents—fell to ruin when the society that birthed the Apparatus collapsed beneath a comet of corrupted ether. The Apparatus remained, sealed in a sanctum of obsidian conduits, until explorers breached the vault seeking relics of power and reawakened the titan's duties. Scholars of the Arcodrome Collective have argued whether the Apparatus follows vestigial programming or something akin to belief; Captain Izel Merk of the Starward Cartographers calls it a 'priest of equilibrium.' Tribes near the Vault of Morn tell of the Apparatus harvesting storms to mend the world's scars and of whole caravans being rerouted—or dissolved—by its indifferent priorities. The Order of Sealed Bearings keeps a catalog of encounters and a single standing warning: never attempt to reboot an Oxyrron without offerings prescribed by the Vault's runic matrix, for its restorative logic treats any disruption as an entropy to be excised.
Imagine a gargantuan humanoid frame assembled from a gleaming, liquid-silver alloy that wrinkles and shifts like quicksilver restrained by armor. Each major limb locks at broad, industrial hinges—riveted rings of blackened steel through which braided techno-organic tendons run like cables and veins. Superimposed on the metal is a latticework of cobalt-blue circuitry that pulses in slow waves; occasional nodes erupt in filaments that probe outward like antennae. Its neck is encased in a section of translucent synthetic dermis—faintly luminescent blue—through which a complex of pistons and membranous diaphragms can be seen moving. The head is an angular visor with three stacked ocular lenses that glow ice-blue; when the Apparatus focuses, the lenses narrow and project thin lattices of light. Surface textures alternate between mirror-smooth alloy, pitted oxidized plates, and bundles of braided fiber-optic sinew. Scale: when standing in a ruined city gate, its shoulder plates rise above the lintel; seen next to a human, its fist is larger than a wagon wheel.
Made with the free LoreKeeper Monster Generator · D&D 5e-compatible stat block · Free to use at your table · Licence
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