By schism rent asunder - David Weber

In the nine centuries since the creation of the world, the Church of God Awaiting has grown all-powerful as the keeper of men's souls. It rules the planet of Safehold with the imprimatur of God Himself . . . and with an iron fist.

Lately, the island kingdom of Charis has rejected the Church's authority. Charis has repelled the Church's first attack and is preparing to strike back. Yet not all those who support the Church are corrupt, and the Church stands ready to use the faith and belief of those blameless souls for its own cynical ends. The gauntlet has been cast down, and full-scale religious war - the ugliest war of all - looms over Safehold.

To prevail, King Cayleb of Charis has one ally with resources not even he can imagine: the mysterious warrior monk called Merlin, who holds the secret knowledge Charis may need to survive. Merlin is Cayleb's adviser, protector, and friend . . . and, secretly, also the cybernetic avatar of a young woman named Nimue Alban, who died before the day of creation itself. Who was born on a murdered world called 'Earth'.