One of the most interesting things about this chapter is how heavily it mirrors Skypiea. We see Sabo talking to a bunch of criminals about a God in Imu. Right after, the God, Imu, decides to destroy the place the person was speaking at.
This is exactly what Enel did to the Skypieans with his Mantra, when Conis got attacked for trying to warn the Straw Hats. Enel stalked them by using his CoO with his ability to intercept electric signals to listen in on everyone's conversations, so he could attack anyone who spoke ill of him, or went against him.
Based on this, I'm assuming Imu has MASSIVE CoO, beyond anything we've seen. If Imu is actually hearing Sabo, the way Enel did, it's possible Imu has a Devil Fruit that allows him/her to sense the speech of people far away (Vibration Fruit, Water Fruit, etc).
@HA001 is right, it really looks like this is setting up Imu and the Final Arc to have heavy Skypiea vibes.