He has done alot already but it's about What xebec really wanted.
This fB picked up when this happened
Xebec declared he will come back one day....to take what he desires.
So, we will see three things here.
1) Xebec going all out to push IMU or make him wary a bit ( it's necessary because IMU did mark Teach as well)
2) A gap between the strongest and the King of the world
3) A future path for BB and Luffy to scale up to that level