Well since Sabo already took an L from a Gorosei and Greenbull was fine, it only makes sense that it will be the admiral's turn to take an L come Egghead. I predict Saturn and Luffy will only briefly clash and the fight will be discontinued, while Kizaru will take an L to even the score and make up for the loss that Sabo and Cobra took at the Reverie.
It's too soon for a Gorosei to fall yet as they were just introduced to be fighters recently, and only revealed to have devil fruit powers this chapter. Kizaru meanwhile, still hasn't returned the favour for giving the Straw Hats their defeat back on Sabaody. It's time Luffy right that wrong from 2 years ago and give Kizaru his L.
There will be no fight with Luffy, just a clash maybe.
Saturn will take conttol of the Seraphins and fight using those; it's the reason he came in the first place.
People who are thinking that Kizaru isn't the main force are in for a big delusion. And the funniest thing is they are saying that after 5 Gorosei + Imu didn't even capture Sabo, who was carrying Cobra. And someone still think Santurn can beat Luffy lol.