I'm a little torn on how I feel about Mihai. On the one hand, I can see getting bored being a problem if you've been alive for centuries. But on the other hand, if I were in his position, I'd like to think I wouldn't resort to putting my friends'--or at least coworkers'--lives at risk, just to keep myself entertained. He's not a hard character to dislike, and his outlook on life is pretty alien, but on some level at least, it's at least understandable. Even if he is an unconscionable jerk.
That said, his decision to send the kids on a near-suicide mission is what spurs the events of this volume forward. The actual mission, itself, isn't nearly as important as the motivation it gives Shiki, an the opening it gives for the introduction of Nobimaru, who seems like he's going to be a pretty major character.
All in all, this is another great volume. It focuses a little more on action this time around, but there's still room for touching moments, humor, and a pretty damn disturbing ending. I'm so glad I picked up a five-pack bundle of these during a sale, because I'd kind of hate to have to wait to read more.