The Pack, though a single being, is multi-part. It manifests itself as a pack of man-sized creatures somewhat resembling wolves. The resemblance is not strong, for they have bare, bone-white skin that barely hides their muscles and tendons from view. Their head appears akin to some savage bird, hooked upward to rip and tear, with no eyes or nose in evidence. Their four limbs are the most wolf-like in appearance, though they end in over-large claws and have a fringe of small mobile spine-like tentacles.
The Pack has its origins from another dimension, and only enters our world though the intercession of Dark powers, or the machinations of fell Sorcerers. Their home-realm is a place of nightmares, an alien world with a sky crowded with many, too-close moons that would seem to scrape the very mountain-tops. A dour sun with frail blue light shines down on this strange realm, with eclipses occurring hourly. But this is a tale for another time...
Abilities and Powers:
The Pack's power is dependent on the number of its members, with its powers of observation, intelligence and fighting ability increased with every member.
Small Pack (1-6 members): Its weakest form, its members are about as formidable as normal wolves with the intellect of an ape.
Medium Pack (7-12 members): Significantly more dangerous, its individual members are as dangerous as fully armed human warriors, and with the intelligence and planning ability of a small military unit.
Large Pack (13-20 members): A lethal threat, each of its members equalling a tiger in combat. The mind is now capable of magic and can call upon rituals dark and powerful, including those that multiply its numbers from captured victims.
The Horde(21+ members): The pack is a foe equal to dragons, or an entire legion of warriors, each member being the match of a polar bear. Its powers of magic make it a deadly threat also in the realm of magic, being able to open rifts to other realms, possibly bringing in others of its type.
A Horde of 26 or more members can choose to split - those smaller would not choose to lose their ritual capability - creating two Large Packs. This is exceedingly rare, even considering the extreme scarcity of The Pack.
In battle, no matter the numbers of the pack, the attacks of the pack will be closely coordinated, with their perfect telepathic communication. A pack capable of spellcasting can use part of the pack to cast spells in combat, with two members required for this purpose. Rituals require the entire pack.
Packs smaller than Large packs cannot normally grow unless nearby an dimensional rift to their own realm, whereupon an additional member has a 10% chance of joining per week.
The Pack has an alien mind and outlook, and views all creatures as potential prey. Only magic of power above their own capability can impress them. A Pack is curious, and may not always attack if not hungry. However, it holds no real concern for life beyond curiosity. A Pack can sometimes be distracted by a sufficiently novel device or image, even if is illusionary.
The pack is intended to be a scalable, deadly encounter suitable for strange locations, even those with little ecologies as they are able to sustain themselves with other sources than normal food.