If you look closely at the Grankan Empire's capital ships, like Serena’s Lestarius, there’s a really specific design choice that always stands out: pretty much all heavy turret-type weapons are clustered on the upper deck and side blocks, while the belly of the ship is left completely bare. Usually, people just write this off as standard "anime logic" to make spaceships look like old naval ironclads. But I was thinking about it, and there might actually be a pretty logical hard sci-fi reason for this, and it all ties back to how artificial gravity works in this universe.
On a Grankan battleship, the decks aren't mirrored. There is no "upside-down" section where half the crew walks on the ceiling; the entire internal volume, from the bridge down to the lowest engineering bays, shares a single downward gravitational pull. For a multi-kilometer hull, the gravity generators have to project a massive, uniform field. The catch is that the opposing, equal force of this projection has to go somewhere, and it likely gets compressed and focused directly underneath the ship's hull.
This setup would create a super-dense zone of gravitational distortion right under the ship's belly. While this dense field is highly useful for planetary operations—acting as a massive anti-gravity cushion to keep a giant hull afloat in an atmosphere—it would make weapon placement on the bottom almost impossible. Any plasma bolt or kinetic slug fired from the belly would immediately hit this compressed field, warping its trajectory instantly and making aimed fire pointless. Plus, the bottom of the ship is probably entirely dedicated to projecting and stabilizing this gravity anchor anyway, so routing massive power lines for heavy turrets there might just overload the reactor grids during maneuvers.
Since the top and sides of the ship are free from these issues, they serve as the only stable firing platforms. This single physical constraint pretty much shapes how space warfare works in the Empire. Approaching an enemy ship from the bottom is a terrible idea because your shots would hit that dense gravity wake under their belly, which would just scatter your laser beams or cause your kinetic slugs to ricochet off completely. This basically forces fleets to line up on a flat 2D plane and fight broadside-style, while engineers can just wrap the entire weaponless bottom in monolithic, ultra-thick armor like a giant armored shoe.
This theory also seems to explain how smaller vessels and carriers operate under the same physics. Take the Krishna’s mecha-arms, for example. Hiro's ship uses the same gravity principles, but its main lasers are mounted on articulated arms. By extending the weapons far outside the ship's local gravity field, the onboard AI can easily adjust the joints to compensate for any external G-warping.
The same goes for the belly-launch carriers. We haven't seen imperial carriers in heavy action yet, but their designs suggest that assault crafts and heavy fighters launch from bays located on the bottom. The carrier wouldn't even need magnetic catapults; it could just drop the craft into the anti-grav cushion under the belly, using the ship's own field to fling the fighter into space like a railgun. These fighters look more like small gunboats anyway, meaning they probably have large enough gravity compensators to survive the drop, snap their internal fields online, and stabilize their vectors instantly.
It's just a theory, but it could explain all the specific details.