Karkinos at the Keel

One-Shot · 6 PCs Lvl 8 · ~3–3.5 hrs · Single trireme · Sharks / Octopus / Nymph / Karkinos

Style: Beasts → Fey parley → Crab boss | Win: Defeat or drive off Karkinos (0 HP or ≤30 HP after Horn)

Ship: 40×50 +15 +25 = 90 ft · mast · 15 ft ram · no second ship.

"When the sacred crab climbs for blood that is not the sea’s, sound this horn — hunger hears the true feast." — Coral Feast-Horn

Major Beats

Nereid herald + Coral Feast-Horn aboard mist-trireme.
Enc. 1: 3 sharks + octopus on oars.
Enc. 2: Thalassa parley / recruit (+ dolphin omen).
Enc. 3: Karkinos climbs the ram; Horn payoff.

Creature List

Creature	E/M/H	Mini
Hunting Shark	2/3/3	×3
Giant Octopus	0/1/1	×1
Thalassa (Nymph)	—/1/1	Sea nymph
Sea Spirit	0–5	×5
Karkinos (Boss)	1	Cancer the Crab

Difficulty

Tier	Adjust
As Written ★	6 PCs · APL 8
Library Standard	6 PCs · APL 8 — Identical to As Written — this guide’s baseline is already 6 PCs at average level 8.
Easier	APL 4–6: reduce minion counts ~30%; DCs −2; boss loses one recharge or legendary option.
Harder	APL 10–12: boss HP +25–35%; +1 legendary action; add a lieutenant or extra wave.

ENC 1 — Blood in the Oar-Wash

Medium · 3 Sharks + Octopus · 4 oar banks AC12/HP12

≥3 oars destroyed → Short Rest only; else Long Rest.
Non-combat: Horn + AH/Religion 3 before 3 (DC 13); octopus still Ath DC 14.
Overboard Ath DC 12; sharks OA.

ENC 2 — The Nymph’s Shoal

Skill/Social · Thalassa + 3 spirits

Show Horn + Pers/Rel DC 14 (Insight 12 = adv). Pearl-net on ram Inv DC 12 → DC 10.
Peace → Thalassa + Delphinus in Enc. 3.

ENC 3 — Karkinos Climbs

Hard · Huge crab via 15 ft ram

AC18 HP168 · 2× Claw +10 · Crush R5–6 Str DC 16 · Deck Slam Dex DC 16.
Horn once: Wis DC 15 incapacitate 1 rd + soft underbelly (AC 15, adv).
Win: 0 HP or ≤30 HP after Horn success this fight.

STAT BLOCKS

Hunting Shark CR2

AC 12 | HP 45 | Swim 40

Blood Frenzy · Bite +6 (2d8+4)

Giant Octopus CR1

AC 11 | HP 52 | Reach 15

Tentacles +5 grapple DC 16 · Oar Grapple · Ink R4–6

Thalassa CR3

Sea Nymph · recruitable

AC 14 | HP 58 · Spell DC 14

2× Tidal Dart +5 · Charm 1/day · Enc3 Help/heal

Sea Spirit CR1/2

AC 12 | HP 22

Hide in spray · Recruit Pers DC 12 → no surprise Enc3

Karkinos CR9 BOSS

AC 18 | HP 168 | Climb 20 · LR 2

2× Claw +10 · Crush · Deck Slam · LA Scuttle

Delphinus

AC 12 | HP 27 | Swim 60

Rescue Breach reaction · Ram +4

KEY ITEM / NPC

Coral Feast-Horn

1/SR: sharks/octopus ≤30 ft Wis DC 13 or move away next turn.
Finale once: Karkinos Wis DC 15 → incapacitate 1 rd + soft underbelly.

Nereid Herald

Motivation: Stop sacred crab frenzy from poachers’ chum.
Secret: True horn reverses hunger; false horns caused this.

Ship Reminder

90 ft deck · 15 ft ram · 0 extra ships · water ring for beasts.

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