Im has an assbackwards way of doing things
Like the holyland is on fire, instead of using the manpower there to stop it, he instead manifests through Gunko to conquer an island so far away that even if he did so what would it even matter bruh your turf is on fire as of now
The Gorosei have been babysitting Imu for a long time, IMO.
Losing Saturn is probably going to hurt their overall operations at a high level.
Everything we've seen from Imu indicates they're the kind of ruler/god who can't handle being told "no", and those people always have an inherent level of stupidity due to their inability to admit their own mistakes.
Also makes me wonder: to what level is Imu trapped in the castle? First the Revs, now whoever this is: Imu seems VERY unwilling to do things in their own territory, Marijoa. Does Imu simply want to hide their presence, or is their some greater reason they can't leave the castle?