L2-25. Ringwall Grot

Why this room?

Troglodytes use the main south way but avoid this pocket, calling it the Bat-Stone. The hum you’ve tracked south is stronger here—caused by a cluster of darkmantles clinging among the stalactites and vibrating the chamber like a drum. Trogs sometimes bait the nest (throwing fish) to discourage pursuit—or drive the creatures at rivals.

Denizens (choose state or roll 1d4)

1. Darkmantle Cluster (6) perched on the roof (MM).
2. Darkmantle Cluster (8) and Violet Fungus (1) rooted in the inner wall’s shadow.
3. Darkmantle Cluster (6); a Troglodyte corpse (picked clean) lies half in a crevice, a steel javelin beneath it.
4. Quiet Nest (no creatures visible): they’re out hunting—return on the next noisy event or in 10–20 minutes (1d2 clusters of 3 each).

Darkmantle Notes (quick-use)

• Ambush: They drop as an action; on hit they grapple and blind the target (Crush).
• Darkness Aura (recharge 5–6): 15-ft radius magical darkness centered on each—multiple auras overlap into a near-solid night.
• Tactics: Drop in twos, flee up on fire or loud percussion, re-form to drop again from a new angle.

Troglodyte Relationship

• Wary coexistence. Trogs skirt the threshold and sometimes toss fish to keep the nest sated.
• If trogs are pursued here: They’ll throw oil or grease near the entrance, then shove foes into the ring while the darkmantles drop.
• Parley clue: A surviving trog mutters “Bat-Stone hate fire—make sky-ink run away,” hinting that fire or bright pulses scatter the creatures.

Hooks & Hazards

• Falling into Darkness: If three or more darkmantles deploy darkness, require DEX save DC 12 when moving faster than half speed; on a fail, the mover bumps/ slips 5 ft (toward a stalagmite or down to prone).
• Fungus Graze (if present): A creature ending its turn within 5 ft of Violet Fungus must save as normal (MM the growth clings to the inner wall where lantern light is poorest.

Treasure & Finds

(search 10 minutes, Investigation DC 13)

• Steel Javelin (fine): trog prize lodged under a corpse; worth 5 gp to surface folk, more to trogs.
• Purse under a slab: 21 sp, 9 gp, a topaz chip (10 gp), and a waxed grease vial (one use as grease on the floor).
• Bone Tube: Map scratch of east tunnels with a skull mark at “Roll of the Measure.” location L2-17. Proving Run — Roll of the Measure
• Amber Beetle in Pitch: A tiny charm that grants Advantage once to a save vs. darkness-blinded this dungeon level (then cracks).

Encounter Balance Tips

• For low-level parties (2–3): use 3–4 darkmantles max; let the hum give a warning.
• For mid (3–4): 6 plus fungus makes a nasty set piece.
• Reward fire, pulsed sound, or clever counter-ambush with a morale break: remaining darkmantles retreat upward until quiet returns.