For example, the "Tamaki must be sacrificed"/"Takuma wants to sake Tamaki from this fate" plotline seems straightforward, suitable for a primary hero. The "oni" within Takuma isn't evil at all, though did do evil things when maddened by vengeance. So good, let's have them kick ass and end up happily together. I would be in favor of that.
I can sort of get Bureau of Medicine guy. He's a sleazeball government bureaucrat, and sleazeball government bureaucrats do evil things like going along with murdering innocent people for the alleged sake of saving the world from Onikirimaru's power.
Mahiro's confession that he'd been brought up to believe that
he'd be the sacrifice, and his talk about altering records, disturbs me, because it sounds like Oni-baba's been playing the long game. This is the problem for me, because every time she opens her mouth, she basically insists on doing the most evil thing possible and commanding or outright lying to everybody else around her to make sure that they don't have the option to try anything
less evil and destructive. I can't help but think that she's either got some specific motive for doing this, or that she's planning a different outcome than everybody thinks she's planning. (Either way, I still want her to die slowly and painfully...a wish I'm probably not going to get, but a man can dream, right?)
I still have no idea what the connection between Sixth Guardian and the rest of the family is, either. But the combination of Mahiro revealing that he knew about being sacrificed, and the little exchange between #6 and Yuuichi, Mahiro, and Shinji makes me wonder if the Guardians knew all along about the "spiritings away"...yet the talk in the forest a few episodes back makes me think that they didn't. It's kind of hard to be a sympathetic romantic interest if you knew that your side was regularly murdering people to use their souls (ew!) as part of a magical seal.
Vier's a homunculus copy of Ohmi's mom, huh? Sounds like the kind of plotline to be explored more in-depth in Ohmi's route. The longer I watch the anime, the more I'd like to play the VN. Too bad no one's likely to localize it and release it for Mac.
Still not sure why Aria isn't all eager to pounce on the Artifacts, though it appears Drei wants to seize the Onikirimaru's power for his own ends, which at least makes sense (though he's clearly out of his depth).
...and we're left hanging to see if Tamaki is going to grow some ovaries and tell Takuma to bust her out of there, or if she's going to take a level of Shoujo Heroine Dumbass ("But I've decided!" have gotta be the three words most likely to cause eye-rolling in the shoujo audience, because they're always at the front end of the implied sentence "...to do something ragingly stupid because I believed a bunch of crap that no one with three working brain cells should, have no self-worth, and have no faith in the only person or people that are actually worth trusting.").