The analyses of the different ways that Diana and Lapis care for the MC are super interesting, and I want to add that Diana has that whole sequence in chapter 6 where she tries to cut through Natori’s sadness like a sword based on the advice she took to heart. It sort of depicts her attitude toward Natori’s problems as something to be removed or defeated by her in a very direct way: she’s simple and straightforward and still figuring herself out, where Lapis is insightful and more established and actively seems to avoid reevaluating herself.
It’s really interesting that Diana has “I am the main character” energy, where it feels like she’s treating Natori as part of her life rather than as a fellow traveler through life the way Lapis does, in part because she’s figuring herself out as a person and Natori keeps telling her just what she needs to hear, is always stepping into roles in her life that might otherwise be filled by others. Natori is, in some ways, attempting to make herself a narratively important background character in other people’s lives with the way she uses her knowledge of the game, but whereas Lapis resists that and has an understanding of her as a future-seer, Diana is just not mature enough yet to challenge the way Natori presents herself, and rather leans into it because that source of goodness and object of affecrion/protection Natalie is a role she really wants in her life. Everything in her life has been uprooted by coming to this school and stumbling into responsibility, and she is trying to make Natalie her thing to hold on to.