Death's Daughter and the Ebony Blade: Volume 7 Exordium

Death reigns supreme as Darmés strikes at last, raising a horde of the undead and declaring himself emperor. Not only that, but his sinister army has dealt a devastating blow to the Eighth Legion. Felix and the Azure Knights, branded as rebels for refusing to bow to Darmés, make good their desperate escape with Emperor Ramza. With the imperial army in close pursuit, they turn to an unlikely source of aid. Over at Kier Fortress, the united forces of Fernest and Mekia remain locked in battle with Rosenmarie, even as undead horrors bear down upon them with Olivia nowhere near to come to their rescue. In the wake of her crushing defeat to Xenia, the death god granting Darmés his powers, her dearest wish came true—she was reunited with Z. But Z has returned for a purpose: to guide her through the final stage of her training. Only when that training is complete will Olivia have any hope of defeating Xenia and stopping Darmés. But by the time she gets back, who will remain for her to save?

[From J-Novel Club]