Despite Miko being a monster like Shiori she gives a different vibe. Shiori is protecting Hinako to eventually eat her. While Miko has watched over Hinako since she was little. Basically a godmother. You can tell she cares about Hinako and her biting her tail and reducing her power.
Then it leads to her dynamic with Shiori. Despite her losing power, that works more in Miko’s favor. Since Shiori knows that Hinako needs emotional support, it is clear that Shiori won’t provide that since she is truly a monster in how she talks. I am not sure if Miko realizes this, but it makes me curious about her line, I’m going to put you into work.
Though the one comment of Hinako thinking Miko will have people when she is gone and not knowing that monsters are more lonely than humans. It’s the good old a long life more than likely implies a lonely life type of deal, I would assume. My guess is monsters themselves don’t have family; they are just born into the world. Lastly, I assume the despair is what attracts monsters to Hinako and if she turns her life around, will she no longer be tasty for Shiori?