The Scariest Book. Zastupa: The Coming Darkness

Evil has come to the quiet and peaceful Vyshny Volochyok. In the remote corners, traces of monstrous witchcraft rituals are found, crops are burning, wells are poisoned, rusalki are rebelling, and even the ubiquitous evil spirits are hiding in fear,... as if sensing a great disaster approaching.
A squad of the Novgorod Forest Guard arrives at Lysa Hora for advice in this tangled matter, and Rukh Buchila, a modest and unsociable recluse, who spends his eternal life in fasting, prayers, and obscenities, agrees to help them out of old friendship, not yet knowing that there will be no way back, help is nowhere to be expected, fate has already passed its sentence, and somewhere ahead, beyond the breaking of the black forests, the sky will soon turn crimson, like blood, and everyone will be left alone with their nightmares.