It Came From A Cold Hell - The Ecology of the Xill in the Fiend Folio & Beyond

The following is based partially on my conversation with DM Raj yesterday & his experiences with the Xill in all of their alien glory in his own games. Make no mistake he makes his player's PC's fight for every inch of space dungeon & salvaged treasure from the depths of his Spelljammer campaign. There are sprinkles & seeds from other OGL sources as we'll see.

So let's get back to the Fiend Folio for a New York minute & my continuing writing for a Godbound rpg campaign. I've been quietly watching & reading of a number of bloggers since 2017 when the Kevin Crawford game came out who have converted Games Workshop 40K material.  But why?! The Fiend Folio already has an otherworldly quisi devil like creature that may or maynot have a chaos cult dedicated to their cause. That cause is the implantation, propegation, & continuation of this invasive planar species straight outta of the Fiend Folio. Yeah, I'm speaking of the Xill.



Hailing straight outta of the Ethreal & into menacing your PC's. The Xill are supposedly ripe to make a comeback in my games! They excellent proto devils just waiting to spread their madness on others as they implant an eggs & spread the infection of their race. A xill stands 4 to 5 feet tall and weighs about 100 pounds. Xills speak Infernal. Make no mistake about it these things are utterly alien & they represent entities from before even the time of gods or Hell itself.  The Xill grapples you and then parazlysis the hapless victim.
Those bitten by the xill must save vs paralyisis or be suffer paralyisis for 1d4 hours.  An xill can lay eggs inside a paralyzed creature. The young emerge about 90 days later, literally devouring the host from inside. A remove disease spell rids a victim of the egg.

The Xill are in the OGL & here we get even more info on them, they have dark vision up to  60 ft. Meaning that these bastards are from a dark environment.They can plane walk but its not at will according to their OGL entry;"

"These planar travelers like to slip between the folds of space to attack enemies as though from thin air. They can cross from the Ethereal Plane with a move action but take 2 rounds to cross back, during which time they are immobile. As a xill fades away, it becomes harder to hit: Opponents have a 20% miss chance in the first round and a 50% miss chance in the second. A xill can planewalk with a willing or helpless creature."

If the Xill sound like an alien entity straight from the Alien 1977 playbook you might not be too far off. Pathfinder in 2015 introduced the Pathfinder Campaign Setting: Occult Bestiary. This gave us the  xill matriarch. This monsterous queen's big advantage over her minions is two fold one is the speed she can implant her eggs & the cult she can create around herself; "a xill matriarch can lay 4d6 eggs in a helpless creature. These eggs hatch in 24 hours, at which point the young consume the host from within, dealing 1 point of Constitution damage per hour per young until the host dies. The young then emerge and planewalk to the Ethereal Plane, if possible."

"Xill matriarchs can take mental control of creatures in which they have implanted eggs as a full-round action. This functions as dominate monster (CL 13th) and works at any distance, even between the Ethereal Plane and Material Plane. The host takes a –4 penalty on the saving throw to resist the matriarch's control. While dominated, the victim is immune to xills' paralysis ability. The matriarch can use greater scrying on the dominated victim at will (no saving throw). A matriarch can maintain one such link at a time; if she wants to use dominate monster or greater scrying on a different creature implanted with her eggs, she must end the effects on her current victim (though she can switch back later)."
It doesn't take much to translate this into an OSR game system & so Xill matriarchs can easily be brought over into the OSR with little fan fare. These alien menaces from the coldest hells around dead stars are exactly the sort of things that the gods would be battling straight out of a Jack Kirby comic book. 


The Apotheosis of the Medici: Cosimo III sat central between his two sons and his brother below him, Palazzo Medici-Riccardi
It doesn't take much to thinking that a group of Xill will come outta of the Ethreal pick on some isloted country village & begin using the place whole cloth as an incubation vessel for their young. The adventurers are part of a strike force of the gods brought in to cleanse the land of this infection when they run into an Xill matriarchs and then things get complicated. The Xill are completly alien & it doesn't matter to these alien things if your PC's are gods,demigods, or adventurers its all a matter of the survival of the species. In many ways this reflects the mind set of H.P. Lovecraft while paying homage to the uncaring nature of Advanced Dungeons & Dragons first edition. 

There are many reasons why the Xill work in campaigns: 

1. The Xill can pop up literally anywhere making them an alien menace of epic proporations. 
2. These bastards have a very dark infernal component to their make up making them easily mentionable as a race in  blasphemous tome. This means that they might easily summoned to the plane Prime ala the summoning spell from Lamentations of the Flame Princess. 
3. Ghosts & other undead resulting from an infection by the Xill might be an early warning for these monsters. 
4. Gods don't like them because they cause havoc among the psychic landscape of worshipers offerin the DM an opportunity to add them to a campaign as a possible side quest. 
5. Xill are excellent 40K stand in menaces that can act as a dangerous one shot or as a possible on going chaos cult within campaigns. 
6. Royals who have an infestation of Xill are going to be under tremedous pressure to deal with them giving opportunity for treasure or more importantly influence. 
7. Crashed space craft, ruined temple complex, deep in the dungeon there are million ways to bring Xill into your campaigns. 
8. Xill infestations could easily disrupt the flow of divine engeries in a campaign bringing to bare the full weight of the gods upon adventurers as their clerics get screwed as the holy warriors of the gods. 
9.  Xill matriarchs are part of a vast array of an alien ecology that the PC's are only beginning to grasp. 
10. The Xill fit nicely into the insanity of many of the megadungeons that populate the OSR & old school landscape giving them a two fold purpose within games. Destroying the campaign from within & taking away valuable populations without for their own reproduction.