I'm such a slowpoke...

[whoopeeragon]

My first impression of the ADS was actually not FFIV but rather FFXII, with the Sphere Rooks:



....and they're located on the Sky Fortress Bahamut.

The Sphere Rooks also have this description:

Small fighter airship of the Imperial army. Gun turrets placed on the keel, and turrets on the deck make this an effective weapon against air and ground targets.

...of which is highly similar in description for Repelling Cannons.

Let's also not forget that Turn 4 has this particular evil thing lurking as well....



....which is the exact replica of FFXII's Spinner-Rook, also found in the Sky Fortress Bahamut.

With the same signature attack of Pox.

(In fact, all the mobs in Turn 4 was lifted from FFXII and FFXIII.)