The Primordial Rus'. 9th Century

You open your eyes. Instead of a familiar ceiling — the smoky rafters and bunches of dried herbs beneath the roof of a long log house. Outside the window — the damp wind from the Dnieper, the distant jingling of bells on livestock, and the far-off sound of an axe. The air smells of honey, tar, and pine needles.
You step outside and notice them. By the stockade stand two: a stocky youth with ash-blond hair, leaning on a shield, and his older comrade — a stern warrior in chainmail, a wolf's-tooth charm on his belt. Their gazes are sharp as beasts'. And a little farther away, by the fire pit, an old volkhv in a tattered cloak stands frozen — his eyes are white as if blind, but they stare right through you.
You know the truth. You know what the locals do not. This forest remembers blood. This burial mound holds more than just bones. And the one everyone calls "the wise one" has in fact made a deal with Nav. And the girl who brings water from the well has long since ceased to be human.
Ahead lie bloody vengeance, sacrifices to Perun, the whispers of berehynias in the night, and the cruel irony: you remember who will betray, who will die, and which idol will fall first. But you cannot change a single word. And you certainly cannot tell anyone that among the knyaz's druzhina already wanders an undead creature wearing the face of a fallen knight.
Welcome to Kyivan Rus', traveler. Be careful: here, the gods are still alive. And they are hungry.