Il castello di Eymerich ("Emerych's Castle") is a book written by Valerio Evangelisti, an Italian historian and writer of historical fantasy.

Peter of Castile is defending Montiel, besieged by the pretender's forces, which consist mostly of mercenaries commanded by a historical figure Bertrand du Guesclin.

Inquisitor Nicholas Eymerich is called in to investigate the use of black magic by the besiegers and the use of cabal by the defenders.

It depicts a group of Dominicans sent by the Pope to the Castle of Montiel in a mission to use demonology against cabalistic magic .

Takes place during World War II in a concentration camp Dora, where Sturmbannführer SS Viktor von Ingolstadt is conducting an experiment to revive a dead body to support his quasi-scientific research concerning electricity.