Rolling thunder.

Could someone explain this? How does Ikazuchi getting a provisional marriage prevent Akatsuki from getting one?

It's not that Akatsuki can't, but now she's going to be dead last. Evidently the Admiral only has one ring to spare at them moment and she was expecting, by virtue of being the eldest sister, to have gotten her ring at the same time or before Ikazuchi. But then Ikazuchi threw a tantrum and the Admiral caved in to her demands, leaving the Lady in an embarrassing position.

Scholastica said:

It's not that Akatsuki can't, but now she's going to be dead last. Evidently the Admiral only has one ring to spare at them moment and she was expecting, by virtue of being the eldest sister, to have gotten her ring at the same time or before Ikazuchi. But then Ikazuchi threw a tantrum and the Admiral caved in to her demands, leaving the Lady in an embarrassing position.

Oh! My confusion stems from that I mixed up Inazuma and Ikazuchi on the previous page. I thought that Ikazuchi was already married.

I agree with nanodesu. That shit is lower than a snake's belly.