[Mithlas]

I'm running a game with an upcoming enemy of a powerful twisted spirit (not quite a minor horror, but it's definitely got that 'love of suffering and corruption') that either is a toxic spirit or is masquerading as one. Any ideas you have (or recommendations regarding pre-made spirits that seem fitting that aren't in the core books, which is all I have) are welcome.

However, I'm not entirely clear on the rules for making spirits. First I want to check: there are only 3 types of spirits: materialization, possession, and inhabitation. Inhabitation and Possession don't quite seem to fit the 'watching its victims in pain from the safety of the astral', so Materialization seems the type to make it.

I know the core book says that spirits use their Force as their attributes when in astral, but does that ignore the modifiers given on all of the spirits in the core book/street magic? Ie a F7 guidance spirit is 7 on everything until it materializes, when it gains that +3 to body?

I've got a good idea of how it acts, but not as much on the things that will probably be important to the characters come game time: its stats. The party has a good mage and a mystic adept that primarily counterspells, but beyond deciding that this spirit is supposed to be a mean threat (at least Force 5, maybe Force 7) I'm not sure what to make of it beyond a likeness to Shadow Spirits like the Nightmare or Shade. Shedim are also close but not quite what I'm trying to make because they're out to kill - if you have a differing opinion or clarifying information, please note it. This spirit is on earth to feed on metahumanity. Part of the story requires it has Masking so the local NPCs think it's a local "toxic shaman"/ecoterrorist shaman who lived nearby until recently, including a little girl with an attachment disorder who thinks it's her father.

As far as powers: I assume Astral Form is something that is innately part of non-insect spirits.
Aura Masking - allows it to manipulate people even who are using Assensing (and the area has a high concentration of Awakened, beyond the girl having Astral Perception).
Energy Drain  - a natural couple to a twisted spirit or minor horror, though given the time span it most likely won't have the chance to turn it against the PCs.
Mimicry
Sapience
Shadow Cloak
Deathly Aura - the entire abandoned marina where it hides is colder than the surroundings, with frost and daily ice forming unseasonally early

[mtfeeney = Baron]

Sounds cool and scary, hire about building it as a free spirit by the rules in street magic?

[RHat]

The other reason it's not a minor Horror:  The Horrors have not been able to come through yet, at all.  I would caution you against changing that fact for your campaign, as the tonal shift could be dramatically away from Shadowrun.  If they came through at this point, everyone would be screwed.

Rules-wise, I suggest using the free or wild spirit rules for this thing and making it a Great Form as well, for that extra punch.

[Crimsondude]

Here's a nasty fucker I made for Artifacts Unbound:

Delduwath (Force 10)

The spirit has no gender identification. It appears only within the Court, and does so as a massive black tree made of shining petrified wood, veins of blackened sap, and pulsing with the erratic movement of something that does not need to move, breathe, or exist in any way with which metahumans are familiar. When it changes forms, it does so to fit its nature, but also to fit the circumstances. It will take on a slightly smaller humanoid tree form, or it will become an emaciated, bone-white human. Being a creature that sustains itself and grows thanks to the fears and thoughts of metahumans, it has developed an interest in them (though if asked by its subjects, it would deny such a thing). It enjoys probing the minds of its victims and testing all of their fears, common reactions (hence the Accident and Confusion powers), and beliefs instead of just going for the obvious kill.

B A R S C I L W Edg Ess M Init IP
12 10 13 10 10 10 10 10 10 10 10 23 2
Astral INIT/IP: 20, 3
Movement: 10/25
Condition Monitor Boxes: 14/13
Armor (B/I): 20/20
Skills: Assensing 10, Astral Combat 10, Con 10, Dodge 10, Intimidation 10, Perception 10, Unarmed Combat 10
Powers: Accident, Astral Form, Banishing Resistance, Confusion, Engulf (as Guidance Spirit, p. 100 Street Magic), Energy Drain (Karma, LOS, Stun damage; see p. 148, Street Magic), Fear, Immunity (Age, Pathogens, Toxins, Normal Weapons), Influence, Magical Guard, Materialization, Mind Link, Mutable Form, Sapience, Shadow Cloak, Silence, Storm

If you want the stats for a less powerful version, let me know. It's a pretty quick conversion.

[Mithlas]

Thanks for the feedback and ideas, I didn't even consider Great Form (although I may simply decide its Deathly Aura is its expression of that because none of the Great Powers really look fitting).

Here's what I have so far:
Croatoan
Force 7, built from rules for free spirit, modified from a Guidance template

Edit: stats:Body 7, Agility 7, Reaction 7, Strength 7, Charisma 7, Intuition 7, Logic 7, Willpower 8, Edge 7, Magic 7
Initiative 14, passes 2
Astral Initiative 14, passes 3
Armor B/I: 14/14
Condition Monitor: 12/12

Skills: Assensing, Astral Combat, Arcana, Dodge, Perception, Unarmed Combat, Sorcery group
Possible Skills (assuming it becomes a recurring threat): Influence group
Powers: Astral Form, Aura Masking, Confusion, Energy Drain*, Enhanced Senses (hearing), Influence, Materialization**, Mimicry, Shadow Cloak, Deathly Aura (modified, cold is constant but it only betrays an aura of trepidation to geomancers or characters with Symbiosis)
Possible Powers: Sapience
Weaknesses: allergy (moonlight, moderate)

Some spirits come to earth out of a sense of curiosity about the world or metahumanity. Some spirits, such as the Shedim, come out of a hatred for life and desire to snuff it out. This spirit, related to shadow spirits, appears to come to earth in order to feed on metahumanity. Innately skilled at slipping through astral space, it clings to the cold and the dark that it seems to exude, patiently but hungrily preying on the lonely, the old, the young and inexperienced. It leaves a chilling but very hard-to-track mark on the environment it stays in, lacking the obvious aura of fear or foreboding of Shedim. Unlike some denizens of the dark, the Croatoan seems equally able to maintain activity in day and night; noted to avoid the outdoors while the moon is waxing, but seems to come out in force during the new moon. Cunning beyond a doubt, but it is unknown if it is truly sapient.

*=either Essence or Karma, I'm not sure which shadow spirits tend towards, or whether it would be a 'stun-damage LOS' or 'physical-damage touch' variant. It's current meal isn't the PCs this time around, so it probably won't matter.
**=Still not sure if this spirit would best be represented with a possession or materialization strain. Thoughts?

[mtfeeney = Baron]

Pretty shadow spirits stick with karma drain, and it seems more like a materialization spirit than a possession.