Redgrit - The Rust Monster

Role in Its Society:

Redgrit is the embarrassment of a dozen dwarf-clans and the secret weapon of three kobold warrens. To most Underdark travelers, he’s just a rust monster—a scuttling nuisance that turns heirloom steel into orange dust. But in the tangle of abandoned mines and slag tunnels he haunts, Redgrit has become something more: a mobile recycling disaster.

Dwarves curse him as the Blight of the Forge, a pest that slipped from the scrap pits and now prowls tool sheds, armories, and battlefield graveyards. Duergar grudgingly respect his utility; some even “farm” his lesser kin in pens to dispose of broken picks and enemy weapons. Kobolds love him. They call him “Great Red-Gut” and occasionally lure him into traps so he can dissolve invaders’ gear at the worst possible time.

Redgrit doesn’t serve any faction, but his presence warps tactics:

• Dwarves hide steel behind stone vaults or switch to stone and bone tools in his territory.
• Patrols change routes after “rust runs” where entire squads came back with ruined armor.
• Underdark raiders whisper about the place where even magic swords went pitted and flaky overnight.

Redgrit is a walking environmental hazard in any region where metal matters.

Appearance Description:

Redgrit is a large rust monster with a shell like flaking terracotta armor. His body is low and segmented, six chitinous legs carrying him in a quick, side-to-side scuttle. Each leg ends in a claw tipped with dark, iron-stained hooks that leave little orange smears wherever he walks.

His back plates are mottled shades of red-brown and burnt orange, crusted with powdery rust. Along his spine, faint ridges look almost like fused scraps of long-digested helms and breastplates. His long, flexible tail ends in a heavy, club-like bulb he uses for balance and the occasional thump against metal.

Most unsettling are his feathery antennae, constantly waving and quivering. They glow faintly with a metallic sheen, almost like they’re dusted in iron filings. When they brush against steel, iron, or even mithral, the metal warps and bubbles as if rotting in fast-forward. His small, black beetle-eyes rarely look at faces—they lock hungrily onto swords, shields, and armor buckles.

If he’s recently fed, his mandibles and antennae drip with a reddish, gritty sludge that smells like wet nails and blood.

Backstory:

Redgrit hatched in a dwarven slag trench beneath an old fortress—one of many rust monster larvae tossed into a pit as “waste processors.” For years, he and his broodmates devoured piles of broken mail, bent tools, and rejected weapon blanks. Their keepers would toss them fresh scrap, jab them away from the intact racks, and curse when one got loose.

During a siege, the fortress forges ran hot. Broken arms and armor rained into the trench in an endless cascade of steel. Redgrit gorged. The vibrations of battle overhead drove him wild, and when a bombardment cracked the slag pit wall, he bolted into the fortress proper, following the richest smell of metal he’d ever known.

He skittered through panicked dwarves and invaders alike, ignoring flesh to lick clean the fallen blades and shattered shields. He tangled himself in the middle of a melee between dwarf champions and duergar shock troops, and by the end, everyone was fighting bare-handed while Redgrit burped rust.

The fortress fell. Redgrit wandered off through the undermines, driven by an instinctive compass for the nearest concentration of metal. Over decades, he has become an urban legend: the monster that ruined a king’s ancestral warhammer, that stripped a duergar execution squad of armor in one shrieking minute, that turned a treasure hoard into a pile of flaky orange dust and one smug, fat bug.

Now he prowls a region of derelict armories, collapsed forges, and forgotten war tunnels, following the faint “scent” of metal through stone.