Spoilers ahead!

So, in the latest chapter, Imu appeared from an Abyss Circle hovered above the skies of Elbaph. This is unlike how the Elders and Knights of the God teleport themselves. 

That Abyss Circle looks a bit familiar. Remember what happened to Lulusia? Sabo said that he witnessed a strange object far in the skies above. 

I think from these two pieces of information, there are three possibilities of what Uranus (World Government's most likely Ancient Weapon) would look like :

1. A massive flying ship (?) or a flying object. Thing is, such thing needs to be hidden from World Government enemies and well, unless the World Government hide it in the barren lands of Red Line or maybe with Imu's powers (what if he can store things inside his grimoire or his Abyss), it would've been found sooner, because such object is too hard to be hidden. Also since it needs to be powered by Mother Flame, how that thing is powered is a bit complicated. (Pretty much sure Mother Flame is a volatile energy source). 

2. Imu is the Ancient Weapon himself. But this is definitely not that makes sense since how does a king, a part of First Twenty Monarchs is an Ancient Weapon himself. Maybe this theory would makes more sense if somehow Imu fused himself with the weapon, or the weapon itself has its own will and thus a sentient one. This theory also implies that Imu consume the Mother Flame himself. 

3. A smaller magical weapon, such as grimoire, magic wand, artifact, amulet, or something like that. 

Either way, I think the revelation of the Ancient Weapons are also should be not that far from now.

What do you think?

Imu and his Ancient Weapon