The Lurker in Shadows

It be a strange beast, the demon called The Lurker in Shadows. It is a thing from the Rift, and a thing from the Centaur Dreaming tree. The Centaurs believe that dreams are real places and the people and beings encountered are real but "fragments" of greater souls scattered across a multitude of worlds and universes. The Lurker doth cross between. This makes it powerful and able to grant wishes - but also unreliable as it draws knowledge and things (or even persons) from across these many worlds where history and association may be very different from our own. It may lie or it may tell a truth, but not from our world and we can not tell. Because of this it may be wisest to use the demon only for physical services, in which it be most formidable. Strangest of all is that it may pull copies of itself from these many worlds where one becomes a pack.

Ayami Noto. scholar. "Lost lore of spirits and occult beings" 2048 T Bronze age kingdom of Epara (Modern eastern Olia)

Lurker in Shadow by Mutterwolf

Summary

The Lurker flies without wings- levitating upto 10 meters off the ground.
The Lurker speaks but no with words. It has no voice. All nearby hear it but none at any distance hear what may be said. It makes neither roar nor snarl, being silent at all times.
The Lurker may turn invisible. but it's pale blue eyes remain visible. It prefers to be nocturnal.
The Lurker may teleport and walk between worlds, or cross the Gauntlet and enter The MIsts or Astral Plane.
The Lurker avoids strong smells. The more stinky, the stronger it is repelled.

The Lurker requires a sacrifice ( Bones: 100Kg if old/ dry. 80 kg of harvested. 60 kg of fresh - 15% of a body wt is bone) upon summoning and in exchange will make one of three pacts:
The Pact of Action: The Lurker will perform one specific action in destroying, killing or performing some physical service.
The Pact of Knowledge: The Lurker will reveal information or lore. (The Lurker makes lore roll at Smarts 1d10 and Lore 1d10). If it doesn't know it will spend 1d6 days and return with some answer.
The Pact of the Wish: The Lurker delivers an enchanted blade of Red Obsidian. It must be used to make 100 sacrificial kills and once charged with the captured souls, will be exchanged for the wish. The Lurker will of course seek to warp the meaning and deliver a cheat.

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Ability scores: 1d10. Pace 6 parry 12 toughness 16. fight 12. athletics d10. Notice d8, stealth d10, Size 4 (+1 wound). Invisibility (except eyes). Fly. (up to 30 ft above ground, pace 6). Detect arcana innate ability. Keen Vision: Ignore range and illumination penalties. Extra limbs: ignore 3 multiaction penalty. Powers: Teleport, plane shift, bolt (cold) 2d10. Bite: str +1d6 AP 2, claws: arcane attack str+2d6. Ap 2. Tentacles 2. reach 2. toughness 14. grapple +2 and then bite. Bone dissolving: The first wound causes -1 penalty on STR, Agil or pace rolls. This becomes -2 on 2nd and -4 on third. On fourth hit to limbs they become rubbery and immobilized. On 5th the bone is gone and a limb is useless, a body wound is bleeding out, head is unconscious and bleeding out.