I was thinking, noticing, today that Taeko hasn't had much of a role in the past many chapters. Her last significant roles were in vol 7. She played "hostess" to Kaoru in chapters 59 & 60, showing him around her grandmother's town, and then she led a ghost-exorcism in the Sakuraba mansion attic.

Since then she has been the well-adjusted capable boring person, while our attention has instead been directed to Tina's life. In vol 12 it was Taeko who hauled a drunk Tina away. In vol 13 it was Taeko who interrupted the tongue-lashing Mayu was giving Tina, and Taeko who had sake at hand for a distracted Miyabi.

It is not as if Taeko is really a boring person. I point to vol 3 ch 24. Taeko was overburdened with study and maid-work, and probably still is to this day. She does have concerns and interests. (But KF doesn't seem to take an interest in them.)

At the time of vol 3 ch 24 Tina was asked about her own studies. "My classes are easy this semester." We have never seen Tina studying or working. Even though she was absent from Japan from about age 15-18, and again at age 20. She can SPEAK Japanese "excellently", but we have good reason to think, because of those absent years, that she has catch up to do in her reading/writing skills.

Those are lapses. KF could have done something more, something a bit differently, with Taeko and Tina.