Nah, I think they have done it before. I mean in the first place it's an upgraded version of Hakoku.
Hakoku:
Hakai:
Even the naming supports that Hakai is an upgraded technique.
- Hakoku means "Conquering a Nation".
- Hakai means "Conquering the Sea".
Kaido asks Mama if she can still perform the attack (implying they've performed such an attack before):
Procrastination finally caught up to me.
But also, I'm painstakingly cutting out all the panels from the chapter. There are also some essays that I should delay until the Viz lands, translation quirks can change so much.
I have a dozen essays to write and only so much time. It's better to get all the preparatory work out of the way first.