The Vexations of a Shut-In Vampire Princess, Vol. 12 (light novel)

When the remaining Fools of Observatory are spotted in the Imperial Capital, the empress rallies Komari and the other Crimson Lords to oppose the organization. However, it quickly becomes apparent that one of the Crimson Lords--Millicent Bluenight--has vanished along with an Extermination Armor that had been confiscated from Observatory. Hoping against hope that Millicent hasn't turned traitor, Komari and the others comb the Imperial Capital for both her and Observatory, all while the Fools...