LOL, author with another great asspull.
Why didn't Master reveal the content of Igarashi's journal to Akari and the rest himself? No point of reading the damn thing when you have a 60+ year "vampire" who was actually there to retell it.
Why would Igarashi give Master(Ryunosuke) the animal syringe, but none of the vaccine to inject Miyabi with? Unless the author going to pull an "Master injected himself with it" stupid plot.
Why didn't Master go with Atsushi the first time when he tried retrieving it? I'm sure Master + Atsushi + Master's daughter could had defeated the hordes of vampires to reach it.
so on and so on, so many damn plot holes.