Dunno why it didn't hit me before but you guys are right, Michiru is clearly autistic. And I'm not sure if the author is going there, but it would be likely then that the monster covering her face represents that, or maybe formed out of the pain of being rejected because she doesn't know how to interact with kids she want to be friends with.
Miko says she paradoxically has no trouble telling how Michiru feels, but the struggle is from her end, as she basically blind to anything else but her very strong feelings/delusions/expectations.
Really didn't expect that wholesome conclusion, it was beautiful. Even funny at the end, there's everything here, we're blessed.
I'm still waiting for a Training Arc! Because no matter how cool it was to see that Hana's kindness was just that powerful, they were nevertheless all blind to the danger they were in the second before it shone.
I may need to stop seeing this like if it was a shonen, but I feel like the world built is just too dangerous for them to stay powerless for so long.