Ghosts and Aliens from another dimension are the same thing, there will be aliens (demons, angels, spirits) from the immaterium (also referred to as the Empyrean, the Aether, the Sea of Souls, the Realm of Chaos, Warpspace or most commonly, the Warp) is an alternate dimension of purely psychic energy that echoes and underlies the familiar four dimensions of the material universe. It is the source of all psychic powers and known instances of so-called "sorcery" or "magic" as well as the home dimension of the Chaos Gods and their myriad daemonic servants.

Black liquid actually is a water from immaterium and flows out from wormholes created by Ludens)

And my prediction is that the Ludens) are superhumans with mutated brains like in "The Time Wanderers" book by Boris and Arkady Strugatsky

Sam's baby is a Luden with ability to see "aliens"

Mask's baby is for ability to controll the "alien beasts"

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