Is This a Zombie?, Vol. 6 (Kore Wa Zombie Desu-Ka?)

Ayumu and his housemates are getting on just as if they were an actual warm (or, in his case, cold) and loving family. And with Eu under threat from a mysterious nemesis known only as the 'King of Night,' the motley crew is tighter than ever as they resolve to keep the 'shady necromancer' safe. But when the resident vampire ninja, Sera, receives orders from home that threaten Eu's well-being, will she turn her back on her new friends?!