It looked like Towa's naming Hiiro was what killed other ogres. Or am I misinterpreting those orbs?
Why would the people even believe that there were "mine toxins"? I am not a miner, but gold mining is normally physical one, there is no chemistry involved of any kind that would release any toxins. I could understand if one of the gold veins had something else deposited in it, but then the source of the would have been pretty obvious.
Overall it was very-very "meh". The only really interesting part was interaction of Diablo/Noir with Violet, since it allowed a peak into what Diablo is, even though it left more questions than it gave answers.
And that ending? It's so bullshit. This have been an issue for most of the series, really, that almost no one dies in it, but this... And the way 2 characters were saved was just like that meme with duct tape stopping water. Killing off Hiiro, who felt mostly pointless (especially since no one of the ogres mentioned him before in any way), would have been the best logical conclusion. Saving him, but killing of Towa could be ok if Violet would still use her body despite void of the contract (which sounded weird in the first place), but saving both... It's just... Childish.
