Landing Beasts are a parasitic race that have co-evolved with Humanity, like the ticks living on a stray dog's back. The blood they draw are human lives.
A Landing Beast enters our universe like a shark breaking the surface of the water. Then, it snatches its prey, and disappears again.
It's attack is never noticed - does an ant see the finger descending to crush it? And then it is gone. Those left behind lament a disappearance not just from their lives, but their very universe. Their loved one, if they still live, could be light-years and millennia away from them. None are ever returned.
The captured person is stored in a "capture sac" and enters suspended animation. Over time, like a rat swallowed by a snake, they are dissolved and absorbed.
From Wolves to Dogs
Landing Beasts are not the only Eldritch beings preying on humans. Even as we were noticed, the Landing Beasts were noticed as well. Through cultists, magic, and feeding pits, the elder races put Humanity to use as their sheep. Sheep need sheepdogs: the Landing Beasts were put to use as well.
The elder races bred them to carry many humans at a time. To consume only a few. Seeking out the kind they most wanted and plucking them, like fruit off a tree.
In time, breeds were created that could transport thousands of people and keep them suspended indefinitely. There are many more Landing Beasts cruising the Outer Dark than ever come to permanent rest on Earth. Like deep space asteroids they make their transits, loaded with capture sacs. In one may be a victim take in just seconds ago. In the next sac, one who has been held suspended for millions of years.
The elder races bred the Landing Beasts into different species. The most notable are the Harvester Beasts, the War Beasts, and the Assassin Beast.
The Harvester Beast
The Harvester Beast is a colossal creature, easily as large a warehouse or a drydock for an ocean-going galley. Adapted instead for space, crashed on Earth it is as helpless as a beached whale. It flails and roars till it dies within a day or two.
The shock of entry into Earth's atmosphere rips capture sacs from the Harvester as it descends. Many are lost, turned up in the atmosphere of pulverised on impact. Many survive however; it is what they were bred for.
Beneath the Harvester's translucent skin the bulk of the capture sacs are visible. A sharp knife and a strong arm is all that's needed to cut down to them. Once a sack is torn loose it begins to liquify. In hours, all that is left is a wet stain in the soil - and a revealed human.
The human does not recover the days more, if they will recover at all. They wonder about, their senses dulled and their muscles weakened by fever. Like moths, they are drawn to bright light in the nights. In this state, "Landing Sickness" they are easy prey for hunters; animal, eldritch, or human. Most humans brought by the landing beasts are young women in excellent health. We can only assume the plans the elder races have for them are no better than those of the Hyperboreans.
The War Beast
The smallest of War Beasts is large as full-grown, bull, African elephant. It is protected by thick armored hide and doesn't fear fire. Under its back armor is a large cluster of capture sacs. The War Beast can survive the impact of crashing on Earth. If it is not killed and cut open it will go on to digest its captured humans.
A War Beast can also seize more. It hides in ponds, mud fields, or peat bogs, springing out to grab passing victims.
A War Beast's victims can be rescued as long as digestion has not begun. The catch is that the War Beast has to be killed, first.
Most War Beasts land well beyond the Mist Wall, into the battlefield of the gods. There, they do not enter into the (direct) affairs of Hyperboreans. Some, however, fall short. There in the muddy, cold, wastelands that surround the mist, they hunt humans, animals, and each other. It is a very unfortunate slaving party that follows a landing beast down to the earth and finds they have come across a War Beast.
The Assassin Beast
Assassin Beasts are sleek, agile, winged hunters. They are often described by Hyperboreans were seen the matter distance, as immense wasps or dragonflies.
The assassin beast comes for only one person. When it arrives on Hyperborea, it sheds its filled capture sac and departs, growing a new one. Some assassin's return to the outer dark. Others remain; spoiled by the easy pickings of Hyperborea. Over time, their ability to return to the outer dark atrophies. They become trapped on Earth, hiding deep in Mountainside caves to emerge and hunt at night. They are the terror of lost shepherds and runaway slaves.
The existence of the Assassin Beast suggests at least one elder race has an unusually deep interest in human affairs. Why would such beings breed a creature to pick out an individual human being across all the billions living through time, and bring them back Hyperborea to be released?
The Bounty of a Landing
Hyperboreans regard Harvester beasts that land short of the Mist Wall as gold spilling from the cupped claws of their gods. The crash site of the Harvester may have naked, disoriented young women in the thousands who may be led into cages just by the light of a burning torch waved in front of them.
The slavers who come for these riches range from solo adventurers to organised teams of hundreds of men. They watch for Landing Beast coming down at night, like shooting stars, and raced to make their claim.
The first slavers to reach a landing have the rights to it - if they can hold it. Faster, smaller groups will take as many girls as they can, bound and thrown over their horses, before larger, better armed groups arrive with cage carts, riding lizards, and mammoths. Opportunists will wait along the edges, avoiding conflict, waiting for those girls who slip too far away for their stronger rivals to bother with. Every corpse has it scavengers, and scavengers and their niches.
If a Harvester lands too close to the Mist Wall, only the bravest and most desperate will raid its carcass. This is because they may soon find other beings turning up - the very ones that summoned the Harvester in the first place.
Farmers do not tolerate pests.
The Summoning of Landing Beasts
Landing Beasts are summoned by eldritch entities to bring young, human females as food and breeding fodder to the Battleground of the Gods - a continent-sized warzone hidden behind in a perpetual mist wall.
However, some human cultures on Hyperborea have learned to summon landing beasts as well. Perhaps they do no more than distract the creatures off their courses. Perhaps they merely bait them, their arcane efforts no better than chum thrown to sharks. In the Shemite creation myth it was their ancient priests who populated Hyperborea by bringing Landing Beasts that carried every other culture.
Let us examine how such a creature may be summoned.
The Ritual
Key to the ritual is the offering of a consecrated human life, almost always that of a slave girl.
The right slave is one with an appropriate horoscope. A slave horoscope is a calculated based on the day and the location a girl was enslaved. It may be kept on a tablet or scroll. However, it is commonly tattooed on, or under a breast, or above the base of the girl’s spine.
Readings vary between cultures but focus on a slave girl’s passion, obedience, and fertility. If a slave’s horoscope shows the strong presence of planets in all favorable zones or “houses,” she is deemed worthy as a sacrifice.
The sacrifice is conducted at an Outer Dark observatory. These are Stonehenge-like structures doubling as an astronomical calendars. The most sacred observatories are those built by races before the coming of Humanity. The ritual can only be performed at certain times of the year, according to the positions of the stars and planets.
Sacrifice-worthy girls will be kept just outside the observatory grounds. They are highly valued and kept under armed guard. Most often they are put on a controlled diet and made to serve only the most senior priests.
When the time comes, a girl is chosen, taken to the observatory’s altar and held down, a cultist holding each of her limbs.
A chant then begins in a pre-human language, the words of which are recorded on stone tablets that are only decipherable by the most maddened scholars.
The first chant is recited before the sacrifice and it is used to call forth the Landing Beast from the Outer Dark. It is (perhaps) best translated as follows:
"Yogsothoth, Great Lord, Hear my plea,
Great Hunter of the Outer Dark, Harken to my call,
By the blood of the sacrifice,
By the power of the stars, I summon thee,
Come forth from the void, and do my bidding."
The slave is then sacrificed. Her blood is used to draw patterns on the ground and the signs of whichever cosmic god the summoner invokes for protection.
The second chant is recited after the sacrifice, and it is used to bind the Landing Beast to the summoner's will. It goes as follows:
"Cthulhu, Lord of the Outer Dark, Hear my plea,
By the blood of the sacrifice,
By the power of the stars,
I bind thee, Great Hunter, To my will,
I command thee to do my bidding."
The summoner and the rest of party then watch to see if a shooting star appears. If successful, it will grow, as a landing beast enters into our universe and de-orbits. It will crash in the vicinity of the observatory - one reason such places are far away from large settlements. War Beasts and Assassin Beasts can then be given further instructions, with the Assassin Beasts being able to re-enter the Outer Dark and strike at the summoner’s command.
If the ritual has failed a landing beast will still come - but it will be enraged and attempt to kill the summoner and their party. An enraged Harvester is no threat; as long as it brings its captives to the summoner, the goal as been achieved. Assassin Beasts and War Beasts however are great dangers. They will kill those who sought to bind them, unless killed themselves.
It's worth noting that this is just one such ritual human summoners may use. Others have been developed throughout the history of Hyperborea. Different gods have been invoked and different chants recited. Some rituals call for the slaughter of multiple slaves. However, the core of the ritual remains the same.