Thoriane

Thoriane, first appearing in Chapter 1, is Phoenix's top assassin. She is the Guardian of Death, essentially a Grim Reaper figure, except instead of escorting one peacefully to the afterlife, she often partakes in the killing of the victim herself. Being a Guardian, she is capable of shapeshifting, but typically remains in either her usual form or a shadowy version of herself.

She is often tasked with teaching new assassins how to kill properly. Her most recent student is Tyr. It's not going so well.