Would love for BB to be the first character to take down an admiral on panel tbh.
Funny, because I think the opposite will happen: BB will be the first pirate
to command Admirals for his own goals.
Long story short:
Mariejois is of obvious French inspiration and the very AK could in some ways be a fictional interpretation of the
Ancien Régime, whose military hierarchy had six spots for
Grand Marshall of the Army. I think this is where Teach's family comes from.
The AK had 6 Generals, one of which was the Marshall D. family. They may have been traitors to the entire AK, or just to JoyBoy's family, that doesn't matter. What matters is that I believe this scheme, King + 6 Generals, will be replicated by EOS.
We've seen lesser variants of it with
Dofla + his seats (4)
Enel + his priest (5)
and with any Yonko + Commanders (3)
Currently, IMU is that king, but s/he only has 5 Generals, in the guise of the Gorosei. Whatever happens on Elbaf and/or with Garp, I think BB will worm his way into Mariejois legitimately and become the 6th Gorosei... only for history to then repeat itself, BB betray the other generals and the king, and usurp the throne.
But before that betrayal happens, BB will be a genuine Gorosei with the power to order Admirals around for his own bidding.
We'll get a Dark Nika + his 3 Marine Commanders wrecking havoc on the way to Laugh Tale.