I think you don't understand that the Holy knights were also there, Saturn was around, probably most of the marines. Also, whitebeard and big mom had their own plans. We know kaido didn't really like xebec. All that's left are shiki and the others. Judging from whitebeard and kaido, the rocks pirates didn't seem like such a good team. The only person I could see staying with rocks are shiki, ochoku, and gloriosa. And that's a small possibility. It looks quite one sided. We even see big mom leaving to open one of the chests in the middle of the battle. The real question is how strong was rocks. In order to to control such a crew and start such a war. Roger, garp, and garling were all after that one guy (ig garling was been after Roger as well). He must have been quite strong to solo all of those forces.
@@CROSS.D.X bro, if don't roger and garp don't defeated him, he probably killed all celestian dragons and to stop xebec, the navy asked roger to collaborate with the navy to stop xebec (plus: for me figarland is strong as whitebeard that time)