It's a Tank. One called the "Kodiak," and is a superheavy weapons platform produced by the Great Belnesarian Empire over a century ago. The only reason it's still in service today is because it's cheaper to make than a proper Skyship, and is roughly as durable as a fully-shielded frigate. Compared to tanks in the real world, though, it looks plainly ludicrous.
As you can see, by the inclusion of secondary turrets and barbette guns ("sponsons," if you will), the Kodiak is in fact a rip off of a certain type of superheavy tank from a certain miniatures wargame whose particular owners are usually quite jumpy about copyright. However, I don't think they've trademarked the concept of "silly tank the size of a house." The original tank this one was designed to resemble is actually very distinctive in appearance compared to the Kodiak; mine is an oversized ordinary tank with a few extra gubbins added. Including Victorian scrollwork. There's no reason to put scrollwork on a tank's armor, and every reason not to, which is precisely why I did it. I'll probably change mine to look less generic and more weird so as not to get any cease-and-desist letters.
Unlike in the real world, tanks are not the basic frontline armor for any major power, including on the Blueworld. Armor Frame technology is widespread, thanks to some meddling by Magi, and even the Soviet Union could build advanced suits of superheavy armor back when it existed. (The Blueworld refers to its Armor Frames as "Hardsuits," and their AFs tend to be less mobile and less technologically cutting-edge but tougher and more reliable.) AFs are highly mobile and can carry weapons as heavy as most armored vehicles in the real world--including real-world tanks. Tanks and other armored non-walkers in the setting, in contrast, make use of the same tech to fill a niche that AFs left open. That is, they hold even heavier weapons than AFs can carry, and have much more armor. Unlike AFs, however, non-walker vehicles are less mobile and not jump-capable. (This, of course, means AFs can jump. And by "jump" I mean "achieve temporary flight." The most mobile AFs are capable of operating fully airborne and can function in much the same way real-world helicopters do.)
And unlike AFs, heavy vehicles can be fitted with high-integrity shield generators. AFs usually use up most of their space for locomotive systems, pilot support, and ammo. As non-walker vehicles rely on simpler methods of self-propulsion, they save up a lot of room for extra defensive or offensive measures that AFs can't carry. Superheavy tanks, in particular, are known to carry shields rivaling that of spacecraft several times their size. The Kodiak superheavy tank happens to be the toughest of this class of war machine.
This Kodiak, the sketch in the upper left, I call "Mama Bear." That's a good a name for a tank as any.