In the Endless Void the soul of a man is waiting, waiting for so long memories are lost, his life before mere flashes of information and memories. How he got here, why or when are unknown.
The soul is reincarnated with unique powers in a fantasy world, part of a series of worlds, this particular world is called a Farworld, known to be mostly barren in mana and resources, situated far from the Core.

What you're getting into:
MC with instinctive psychic powers in a fantasy world of swords and magic. No litRPG, no level ups, no skill screens.
MC is not a Human, MC is inhabiting a Human host, as required by the fact they're a Doppelganger.
MC cannot use magic because she can't use mana. MC also can't use aura (warriors) for the same reason. But the MC has her own power from the Void as before unseen in this universe. The larger the MC's brain gets the stronger her abilities become, but they also get stronger through regular use.