Itโs so interesting that Harribel actually refuses the label as King or Queen because she knows if she does accept that role she will be forced into a death battle with Grimmjow.
Yet her appearance in the Hell arc seems to indicate her power has evolved to coincide with position as ruler, especially given her Zanpakuto has evolved drastically. I have a feeling her crown came from this process.
And she seems to have allowed an Arrancar (likely Roca) to create her new Royal attire.
So that begs the question.. has Grimmjow abandoned his desire to be the King? Or have the two come to an agreement on how they can rule Hueco Mundo together?
Perhaps they have reached a middle ground where Grimmjow is โKing of Hueco Mundoโ while Harribel is โQueen of the Hollowsโ