Home >Game Mastering >Bestiary >Creatures by Type >Monstrous Humanoids >

Swarm Xersk

Swarm Xersk CR 16

XP 76,800
CE Medium monstrous humanoid
Init +3; Senses blindsense (vibration) 30 ft., darkvision 60 ft., see invisibility; Perception +33


HP 255
EAC 29; KAC 30
Fort +14; Ref +16; Will +21
Defensive Abilities Swarm mind;
Immunities acid, fear effects


Speed 30 ft., climb 20 ft., fly 30 ft. (Ex, clumsy)
Melee claw +25 (6d8+19 S)
Offensive Abilities demoralizing gaze (60 ft., Will DC 24), siphon fear
Spell-Like Abilities (CL 16th)

1/day—mass inflict pain (DC 26), mind thrust (6th level, DC 26)
3/daycrush skull (DC 25), feeblemind (DC 25), greater command (DC 25), greater synaptic pulse (DC 25)
At willfear (4th level, DC 24), mind thrust (4th level, DC 24)
Constantsee invisibility


Str+3; Dex +3; Con +5; Int +7; Wis +10; Cha –1
Skills Acrobatics +28 (+20 to fly), Athletics +28 (+36 to climb), Sense Motive +33
Languages Shirren; telepathy 100 ft.


Demoralizing Gaze (Su)

A Swarm xersk’s numerous unblinking eyes sow doubt in the minds of creatures that look into them. A non-Swarm creature within 60 feet of the Swarm xersk that fails a DC 24 Will saving throw gains the shaken condition for 1 round. This is a mind-affecting effect.

Siphon Fear (Su)

As a standard action, a Swarm xersk can establish a parasitic psychic connection to a single creature with the shaken, frightened, or panicked condition. A target creature must succeed at a DC 24 Will saving throw or the Swarm xersk latches onto it mentally and begins siphoning the victim’s fear; if the creature gained the condition from one of the Swarm xersk’s spells or abilities, it takes an additional –2 penalty to this save. At the beginning of an affected target’s turn, it takes 2d6 damage, and the Swarm xersk regains Hit Points equal to half that amount (minimum 1). A Swarm xersk can be simultaneously attached to a number of victims equal to half its Wisdom modifier (5 for most Swarm xersks). An affected creature can attempt a new saving throw at the end of each of its turns to break the psychic connection and end the ability’s effects. The effects of siphon fear end automatically if an attached creature’s condition is removed.

This is a mind-affecting effect.


Environment any
Organization solitary or cult (1 plus 5–30 Swarm creatures)

There is a seemingly infinite variety of Swarm components, as the species adapts and creates specialized spawn to counter the many obstacles it faces in its effort to devour the galaxy.

A Swarm dissolver’s main focus is to protect smaller Swarm components and provide an impenetrable front line during combat, incinerating the most formidable foes while also accompanying corrovoxes, mindreapers, and other Swarm shock troops when they swoop in to clean up after a battle. A dissolver’s exoskeleton is thicker than that of most other Swarm creatures, but its most prominent offensive feature—sturdy horns that curl back toward the dissolver’s body— are surprisingly not its primary weapons; these horns instead function as a last-resort defense, allowing a dissolver to fling enemies away with a mighty shove. A dissolver’s main mode of attack is actually hidden between its mandibles: two vascular conduits pump highly corrosive and combustible chemicals from within separate glands in the dissolver’s abdomen. These chemicals are inert when separate but explode when combined, in a conflagration of acid and fire. Like many other Swarm components, a dissolver bears a set of insectile wings, but they aren’t powerful enough for the massive, heavy creature to fly.

Swarm xersks are a rare sight, and in fact only a handful have been seen by members of other species who lived to spread news of their existence. These creatures rarely resort to physical attacks, instead relying on their potent psychic abilities to mentally assault and frighten intelligent creatures.

These bizarre Swarm components have large, crested heads covered in a horrifying array of staring eyes. Those who look into a xersk’s eyes for even a few seconds begin to question reality, and may eventually lose their hold on it altogether.

Superficially, xersks appear to exhibit more free will than most Swarm components. They can often be found alone, quietly observing a geographical feature or distant constellation. Despite this odd behavior, xersks are still very much a part of the Swarm’s hive mind, and like every Swarm component, they act solely to further the Swarm’s machinations, no matter how nebulous their demeanor might seem to outside observers.

Section 15: Copyright Notice

Starfinder Alien Archive 3 © 2019, Paizo Inc.; Authors: Saif Ansari, Kate Baker, John Compton, Adam Daigle, Katina Davis, Eleanor Ferron, Crystal Frasier, Leo Glass, Sasha Lindley Hall, Amanda Hamon, Thurston Hillman, James Jacobs, Jenny Jarzabski, Virginia Jordan, Jason Keeley, Natalie Kertzner, Luis Loza, Lyz Liddell, Ron Lundeen, Crystal Malarsky, Robert G. McCreary, Hilary Moon Murphy, Adrian Ng, Joe Pasini, Lacy Pellazar, Samantha Phelan, Jessica Redekop, Simone D. Sallé, Michael Sayre, Owen K.C. Stephens, James L. Sutter, Jason Tondro, Diego Valdez, and Linda Zayas-Palmer.