Locked tomb trilogy

The Emperor needs necromancers. The Ninth Necromancer needs a swordswoman. Gideon has a sword, some dirty magazines, and no more time for undead nonsense. Brought up by unfriendly, ossifying nuns, ancient retainers, and countless skeletons, Gideon is ready to abandon a life of servitude and an afterlife as a reanimated corpse. She packs up her sword, her shoes, and her dirty magazines, and prepares to launch her daring escape. But her childhood nemesis...

"Her city is under siege. The zombies are coming back. And all Nona wants is a birthday party. In many ways, Nona is like other people. She lives with her family, has a job at her local school, and loves walks on the beach and meeting new dogs. But Nona's not like other people. Six months ago she woke up in a stranger's body, and she's afraid she might have to give it back. The whole city is falling to pieces. A monstrous blue sphere hangs on the...