Well, I just witnessed the coolest thing I've ever seen in this game. However, if you don't want to know anything about the latest JP content that won't hit Global for quite some time, you should probably stop reading.
The new raid boss is the Buster Call, a Boss Rush of Marine Vice Admirals, ending with Momonga. Naturally, each boss comes with Marine minions to back them up.
So, first try on Expert, I brought in DEX Mihawk, INT Mihawk friend, Montblanc Noland, Mr. 1, Whitey Bay and Usopp. I work my way through, somewhat following the Gamewith guide, but mostly flying by the seat of my pants. I manage to limp my way to Momonga with all my specials ready to go.
The sub-20% special on pretty much every one of these Vice Admirals is sort of new--they call for reinforcements, swapping out their already beefy minions for a fresh set of even beefier, evolved Marines, minus any debuffs you might have applied, such as turn delays.
I drop Usopp and DEX Mihawk to start. Matching orb on Bay and Noland (both INT), so I activate Noland, who orb multiplies like Kaku or Coby, and Mr. 1 for the Slasher boost. I hit Momonga hard with a mix of Perfects and Greats, but I completely forget about the call for reinforcements. Momonga drops to 17%, and calls in a new set of Marines, two of which will attack next round and kill me.
However, INT Mihawk's special deals 50% of whatever damage you dealt last round. I trigger Mihawk, and he hits everything for around 150,000, wiping the map in one spectacular, satisfying sword swipe. Momonga's poster drops.
TL;DR, Mihawk dramatically cuts down a Marine Vice Admiral right after he calls for reinforcements, like something out of one of those Japanese cartoons.