Final Fantasy Record Keeper XI: More Expansions, More Salt!

[SerTabris]

I’d suggest checking the various Books of Trials (home > Special Missions in top right > Acolyte Archives).

That makes sense, but I've done those. I have I-X complete (and the Book of Scrutiny), and 'Book of Creation I' that asks me to do Magicite dungeons is open, although tapping there still tells me the dungeons themselves are locked. (Wait, do I need to finish the other Books of Trials up to XV? I thought some of them were added after the Magicite dungeons, so that would seem odd.)

EDIT: Well, I figured it out; it was the 'master a dungeon of difficulty 220 or higher' requirement.