Module
Kruthik Lair (Brood Nest & Queen)
Optional side delve beneath Tower C — Aliens-feel subterranean brood nest with eggs, adult kruthiks, and queen.
Module — Kruthik Lair (Brood Nest & Queen)
Status: Ready to run. Optional tactical side-dungeon for 2nd-level adventurers seeking Ethium stones and ancient relics.
Canonical PDFs & Guides:
- Full Ethium Session Module (PDF) (sections 11–17: Kruthik rooms, tombs, queen, egg stones)
Prior Module: Ethium Pool Hub Module
Overview & Dungeon Background
Tucked beneath the ruins of Tower C on the Ethium plateau lies a tight 3-room subterranean nest carved out by Kruthiks — chitinous insectoid predators attracted to the raw magical energy of unrefined Ethium Stones.
Garnel Stoneblender can mark the location of the nest from rumors overheard while captive. The dungeon has a distinct Aliens survival-horror feel: narrow 2.5-foot crawlspaces, skittering claws in darkness, pulsating egg sacks, and an aggressive Kruthik Queen defending her brood nest.
DM Secret — Plateau Tunneling: The rampant tunneling of kruthiks and Grey Burrowers across the plateau is the actual cause of the eastern pool cave-in (DC 12 check to spot clawed side-tunnels while excavating the pool rubble).
Key Areas & Read-Aloud Descriptions
Room 1 — Swarm Tunnels
Narrow stone passages pocked with burrow holes and covered in fine grey dust.
Read Aloud: The tunnel shrinks to a tight stone passage barely three feet wide. The rock walls are riddled with smooth, claw-carved holes. Dust drifts down from the ceiling as a frantic, multi-legged skittering echoes from all directions.
- Movement Hazard: Passages are tight (2.5 to 3 ft wide); Medium creatures treat this area as difficult terrain.
- Encounter: 5–8 Young Kruthiks.
- Tactics: Start with 5 on the board. Kruthiks emerge from wall holes to surround PCs using Pack Tactics. If PCs advance easily, bring in 2 more from rear holes on Round 2.
Room 2 — The Brood Chamber
A humid subterranean cavern filled with wet, translucent egg clusters.
Read Aloud: Humid, foul-smelling air fills a wider cavern. Hanging from the ceiling and coat-rimming the stone floor are translucent egg sacks glowing with pale blue light. Four-legged chitinous horrors with razor mandibles crouch over the brood, clicking their pincers in threat.
- Encounter: 2 Adult Kruthiks + 3 Young Kruthiks.
- Egg Pressure Rule: If an area spell or attack strikes an egg cluster, or after 2 rounds of combat, 1d2 Young Kruthiks hatch from the sacks. Egg clusters have AC 10, HP 5 — destroying them prevents hatching.
Optional Side Vault — Explorers’ Crypt
A quiet side alcove containing ancient dwarven coffins webbed over with kruthik secretions.
Read Aloud: A low-ceilinged crypt branches off the brood chamber. Broken stone coffins lie covered in sticky web strands. Wrapped in webbed cocooning against a sarcophagus rests the dried skeleton of a human adventurer, a leather satchel still strapped to its chest.
- Encounter: 3 Tomb Skeletons (if sarcophagi are disturbed).
- Explorer’s Kit Loot:
- 2 × Potion of Healing (2d4+2 HP).
- 18 gp, 7 sp, 100 ft silk rope, thieves’ tools.
- Journal Scrap: “They were drawn to the stones like moths. We thought we could take them. We were wrong.”
- Stone of Echoing Vitality: Minor relic (Bonus Action: heal 1d6 HP and gain +1 to next saving throw once per day).
Room 3 — Queen’s Vault
A colossal chamber lit by glowing Ethium crystal clusters embedded in the rock.
Read Aloud: The cavern expands into a towering vault dominated by a massive cluster of raw, glowing Ethium stones. Clinging to the far wall like a giant armored scorpion is a colossal Kruthik Queen, her red compound eyes fixing upon you as hundreds of tiny young crawl over her chitinous back.
- Encounter: 1 Kruthik Queen / Elder + 2 Young Kruthiks (starting guards).
- Four-Phase Queen Boss Fight:
- Phase 1 (Full HP): Queen hangs back on high walls, spitting acid while Young engage.
- Phase 2 (HP $\le$ 40): Queen shrieks, spawning 2 additional Young Kruthiks from wall holes.
- Phase 3 (HP $\le$ 30): Queen enters melee range, making 3 attacks per turn with razor mandibles.
- Phase 4 (HP $\le$ 20 — Final Push): Queen becomes enraged, gaining Advantage on all attack rolls.
Encounters & Creature Stats
Swarm & Brood
| Creature | AC | HP | Attacks & Traits |
|---|---|---|---|
| Young Kruthik (×5–8) | 12 | 9 | Claws +4 (1d4+2). Pack Tactics (adv. on attack if ally is within 5 ft). Keen Smell. |
| Adult Kruthik (×2) | 14 | 22 | Multiattack: 2 Claws +5 (1d6+3) OR Acid Spit +4 (1d6+2 acid, range 30 ft). Keen Smell. |
| Tomb Skeleton (×3) | 13 | 13 | Shortsword +4 (1d6+2). Vulnerable to Bludgeoning. |
Boss Lair
| Creature | AC | HP | Attacks & Traits |
|---|---|---|---|
| Kruthik Queen / Elder | 16 | 55 | Multiattack: 2 Mandible Scythes +6 (2d6+4) + 1 Tail Spike +6 (1d8+4). Acid Spray (Recharge 5–6: 15-ft cone, 3d6 acid, DC 13 DEX half). Enrage at $\le$ 20 HP. |
| Egg Cluster | 10 | 5 | Destroying prevents 1d2 young from hatching. |
Treasure & Rewards
- Ethium Stones: 2–3 unrefined Ethium Stones embedded in the queen’s egg mass (requires DC 12 Sleight of Hand / DEX check to extract cleanly without cracking eggs).
- Stone of Echoing Vitality: Relic found in the crypt (Bonus Action: heal 1d6 HP + 1 save boost once/day).
- Explorer Coins: 18 gp, 45 sp, 2 × Potion of Healing.
Key NPCs
| NPC Profile | Role & Personality |
|---|---|
| Garnel Stoneblender Profile | Provided rumors of the crystal nest beneath Tower C. |
Maps & Visual Assets
| Asset Name | View Link |
|---|---|
| Tower C / Krutick Lair Map |  |
| Ethium Pool Dungeon Map |  |
| Beyond the Pool Cavern Map |  |
Related Documentation & Links
| Category | Reference Link |
|---|---|
| Session Plan | Ethium Pool Session Plan |
| Session Logs | Session 3 Play Log · Session 4 Play Log |
| Related Module | Ethium Pool Hub Module |