User blog comment:Quna/Mikasa and Levi/@comment-1327106-20170728163829

I agree that Mikasa is extremely static and in need in character development. If Eren is not in immediate danger a lot of her manga panels are spent silently hanging around near him, which isn't very interesting.

But from a storytelling perspective the mentor pupil dynamic has already been established between Eren and Levi and I don't think there's the narrative room for him to spend a lot time with a second. When you look at how Levi pushes Eren, it's generally about making choices and owning up to the consequences. That won't work with Mikasa, because she doesn't care about the consequences as long as she makes the choice she wants.

I also don't think he's terribly interested. He asks about her lineage during the Uprising arc, but doesn't approach her at all in the weeks in between the crowning of Historia and the return to Shiganshina, which was an extremely important mission because they knew they would be fighting the Armored, Colossus, and most likely the Beast Titan as well.

Granted Marley is bigger than all of that, but until that point, reclaiming Shiganshina was the greatest mission of their lives and Levi didn't bother training her, so I don't think it would naturally come into his head just because there's a new greater mission. (Maybe if someone else suggested it, but he wouldn't on his own.)

I'm also not sure this would really develop her character. Mikasa and Levi have clashed before, so we know what that looks like. Levi could physically train her, but I don't think he'd be the one to teach her to give Eren space, because his own communication skills are pretty stunted. (No one should learn how to be a human being from Levi.)  She would need someone else for that.