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Hydra CR 6 (Combatant)

XP 2,400
N Huge magical beast
Init +1; Senses blindsense (scent) 60 ft., darkvision 60 ft., low-light vision; Perception +18


HP 90
EAC 18; KAC 20
Fort +10; Ref +10; Will +5
Defensive Abilities head regrowth, hydra regeneration, unflankable; DR 10/slashing


Speed 20 ft., swim 20 ft.
Melee bite +17 (1d8+11P)
Multiattack 3 bites +14 (1d8+11P)
Space 15 ft.; Reach 10 ft.
Offensive Abilities reactive heads, swarm of heads


Str +5; Dex +1; Con +3; Int -4; Wis +2; Cha +0
Skills Athletics +18, Intimidate +13, Survival +13
Other Abilities hold breath


Head Regrowth (Ex)

A hydra has a number of heads equal to its CR. A creature can attempt to sever one of the hydra’s heads by specifically targeting it and dealing damage equal to (Hit Points divided by CR = 15). A head that is not completely severed returns to full Hit Points at the end of any creature’s turn.

A hydra can regrow a severed head using Hydra Regeneration. A creature can prevent this regrowth by dealing acid or fire damage to the stump, cauterizing it. Single-target acid or fire effects need to be targeted at a specific stump, but effects that deal splash damage or affect areas covering the hydra’s whole space cauterize all stumps if they deal acid or fire damage.

If the attack that severs a head deals any acid or fire damage, the stump is cauterized instantly. If all of the severed heads are cauterized, the hydra dies.

Hold Breath (Ex)

A hydra can hold its breath for a number of hours equal to its Constitution modifier before it risks drowning.

Hydra Regeneration (Ex)

The hydra has regeneration equal to 3 x the number of heads it has (regeneration 18 for a CR 6 hydra). If a hydra’s body is missing any heads and the remaining stumps have not been cauterized, the hydra attempts a DC 25 Fortitude save after it regains Hit Points from regeneration. On a success, one uncauterized stump regrows two heads; on a critical success, two uncauterized stumps regrow into two heads each. The hydra can never grow more than double the number of heads it ordinarily has. The hydra’s regeneration only fully deactivates if all its heads are severed and all stumps are cauterized, at which point it dies.

Reactive Heads (Ex)

A hydra gains an extra reaction per round for each of its heads beyond the first, which it can use only to make Attacks of Opportunity. It can’t use more than 1 reaction on the same triggering action, even if a creature leaves several squares within its reach, and the hydra must use a different head for each Attack of Opportunity it makes. Whenever one of the hydra’s heads is severed, the hydra loses 1 of its extra reactions per round.

Swarm of Heads (Ex)

As a full round action, the hydra attacks a single target with its heads, overwhelming its foe with multiple attacks and leaving almost nowhere to dodge. The target must make a DC 14 Reflex save.

The hydra deals its normal bite damage plus 1d6 for each head beyond the first it currently has. The target takes half damage on a successful saving throw.


Environment marshes
Organization solitary

Hydras are deadly creatures that dwell in fetid swamps and waterways. These creatures have huge bodies and a mass of serpentine heads.

It is about 20 feet long and weighs 4,000 pounds (400 bulk). The Lernaean Hydra of legend possessed nine heads, but the hydras of a starfaring world can possess any number.

A hydra is an especially deadly monster, as whenever a head is severed, two new ones grow in its place.

A hydra is not very intelligent, about as much so as an animal. They usually live alone in swamps, and are generally the most dangerous predator in the area they inhabit.

Section 15: Copyright Notice

Starfarer Adversaries: Legacy Bestiary © 2020, Rogue Genius Games LLC; Author: Jacob E. Blackmon; Additional work by: Owen K.C. Stephens. Produced by Owen K.C. Stephens.