Cetus • Odyssey of the Dragonlords

Habitat: Underwater; Treasure: None

The cetus is a nightmare given form, a leviathan that prowls the abyssal depths of the ocean. It resembles an impossibly massive shark, its silhouette enough to shatter a sailor’s nerve. These behemoths reach lengths exceeding 60 feet and likely tip the scales at over 100 tons.

Ambush Predators#

Among all ambush predators—whether of land or sea— none are as formidable as the cetea. They are patient hunters, shadowing their prey from the gloom, vanishing into the depths, only to return from below in a sudden, merciless strike. To them, nothing is off-limits, not even creatures that should, by all reason, be beyond their reach such as krakens, livyatans, and monarch whales.

Ancient Monsters#

Cetea are ancient creatures, often living for thousands of years. Their skin is mottled and decayed, marred by both old scars and fresh wounds. Despite their incredible strength, they heal more slowly than mortal beings, giving them a perpetually wounded appearance. This ghastly appearance often leads sailors to mistake them for undead creatures.

Random Gullet Treasure

1d20	Gullet Contents
1-5	Nothing
6-10	Roll ten times on the 1,000 GP Gemstones table in the Game Master’s Guide
11-17	Roll once on the Armaments—Rare table in the Game Master’s Guide
18-19	Roll once on the Armaments—Very Rare table in the Game Master’s Guide
20	Roll once on the Armaments—Legendary table in the Game Master’s Guide

Gullet Treasury#

Some of the items the cetus has eaten in the centuries it has been alive can never be digested and remain within its gullet. These items can be recovered after the cetus has been killed, but they can also be used by a creature that has been swallowed. See the Random Gullet Treasure table for what can be found.

Cetus

Gargantuan Monstrosity, Chaotic Evil AC 16 Initiative HP 297 (18d20 + 108) Speed 0 ft., Swim 80 ft. MOD SAVE MOD 30 +10 +10 14 +2 Str Dex Int 6 –2 –2 Wis 10 +0 Skills Perception +5, Stealth +12 Senses Blindsight 90 ft.; Passive Perception 15 Languages None Challenge 15 (13,000 XP; PB +5) Traits Blood Frenzy. The cetus has Advantage on melee attack rolls against any creature that doesn’t have all its hit points. Legendary Resistance (3/Day). If the cetus fails a saving throw, it can choose to succeed instead. Water Breathing. The cetus can breathe only underwater. Actions Multiattack. The cetus makes two Bite attacks.

Bite. +12 (22) Melee Attack Roll: +15, reach 5 ft. Hit: 36 (4d12 + 10) Piercing damage. If the target is a Huge or smaller creature, it has the Grappled condition (escape DC 23), and it has the Restrained condition until the grapple ends. SAVE MOD SAVE +2 22 +6 +6 Con Bonus Actions +5 Cha 8 –1 +4 Swallow. Strength Saving Throw: DC 23, one Large or smaller creature Grappled by the cetus (it can have up to two creatures swallowed at a time). Failure: The target is swallowed by the cetus, and the Grappled condition ends. A swallowed creature has the Blinded and Restrained conditions, has Total Cover against attacks and other effects outside the cetus, and takes 21 (6d6) Acid damage at the start of each of its turns. If the cetus takes 40 damage or more on a single turn from a creature inside it, the cetus must succeed on a DC 20 Constitution saving throw at the end of that turn or regurgitate all swallowed creatures, each of which falls in a space within 5 feet of the cetus and has the Prone condition. If the cetus dies, any swallowed creature no longer has the Restrained condition and can escape from the corpse using 20 feet of movement, exiting Prone.

Reactions Savage. Trigger: The cetus reduces a creature to 0 Hit Points with its Bite attack. Response: The cetus makes a Bite attack against the target. It the attack hits, the creature is killed. If the target is Large or smaller, the remains of the creature are swallowed by the cetus. Legendary Actions Legendary Action Uses: 3. lmmediately after another creature’s turn, the cetus can expend a use to take one of the following actions. The cetus regains all expended uses at the start of each of its turns.

Lunge. The cetus moves up to half its Speed, and it makes one Bite attack. Dive. The cetus moves up to twice its speed straight down. Opportunity Attacks have Disadvantage against it while moving in this manner. If it moves more than 150 feet down, has a creature Grappled, and that creature does not have a Swim Speed, then that creature must succeed on a DC 19 Constitution Saving Throw or have the Incapacitated condition until the end of the cetus’s next turn. The cetus can’t take this action again until the start of its next turn.