Ghost in the Razor: Ghost Exile, Book 4 (Unabridged‪)‬

Caina is the ghost circlemaster of Istarinmul, leader of the emperor's spies in the city. She has hindered the malevolent plans of the sinister Grandmaster Callatas, but has been unable to defeat him. Callatas has slaughtered every foe who ever challenged him, and Caina may be next. Cassander Nilas is a ruthless magus of the brutal Umbarian Order, and seeks to destroy the emperor. At last he has found the key to the downfall of the empire.

All he needs to do is kill Caina Amalas, and the empire will burn. Morgant the Razor is an assassin of legend and myth. He vanished a 150 years past, but he may hold the key to Caina's victory.

Or her final defeat.