The Vexations of a Shut-In Vampire Princess, Vol. 10 (light novel)

A showdown six centuries in the making! Following their victory over Star Citadel, Komari and Spica set out on a journey with a common goal: gather the Netherworld's Dark Cores, unseal Spica's friend at the God Slayer Tower, and stop the wars erupting across the realm.Their plans quickly go awry, however, when a mysterious individual appears, claiming to be a member of an organization called Observatory. Six hundred years ago, this man crushed Spica's dreams, and now he's returned to kill her and Komari in an effort to uphold the status quo. After barely escaping with their lives, Komari and her friends travel to the Holy Lehysian Empire in search of a Dark Core, only to find they've been framed for inciting the recent outbreak of conflict. With nearly everyone turned against Komari, Spica, and their allies, a desperate battle begins over the fate of the Netherworld!