- 1. First thing we learn is that Rocks kidnapped (not killed) 5 kings.
- 2. Imu immediately assumes that the kidnapped kings are hostages to be used against him
- 3. Rocks knows that it won't work against Imu but says holy land is in chaos
We also get Imu immediately knowing that kings are to be used as hostages from the way they were kidnapped.
But we never get resolution with kidnapped kings, instead the next thing we hear is that Xebec injured an Admiral (someone who is less politically important than kings) and Xebec running away with no kings.
So either kidnapped kings served no purpose and was just random ass event that Rocks did for no reason
or they did serve purpose as intended hostages.
And there's only 1 big event that happened in the reverie and overshadowed 5 kings being kidnapped and the only possible reason to use į kings as hostages - Admiral being murdered.