Ghost undying (world of the ghosts short story)

Sicarion is an assassin without equal, skilled with both sword and spell, and no foe has ever escaped his devilish cunning. Yet when he accepts a contract to kill a renegade sorceress calling herself the Moroaica, Sicarion realizes he may have made a mistake. For what can an assassin do against a woman who has already died as many times as the Moroaica?