Yu Lian knew that these warships were the famous Canticle-class arsenal ships. Though called arsenal ships, they were nearly as large and heavy as a smaller battlecruiser. They had an extremely specialized design: their speed, range, and defenses were all unsatisfactory, and they were prone to breakdowns. They were the kind of ships that spent half the year in maintenance and half in service, flawed from the start. But they were equipped with a massive fortress cannon.
The ships didn't even have a single secondary gun or anti-aircraft gun, yet they carried a fortress main gun with an outrageous amount of firepower.
Some Alliance military designers apparently thought that configuration was still a little problematic. They argued that the ships should at least have some secondary guns; otherwise, they just wouldn't feel safe. But then some clever higher-ups pointed out that the whole point was to make an extreme design. The ships couldn't survive without escort vessels protecting them, so what was the point of talking about feeling safe? They might as well push their strengths to the limit.
In short, every gram of a Canticle-class arsenal ship's mass was devoted to that powerful fortress cannon.
As you could imagine, if one of these ships were isolated, it might not even survive an encounter with an armed merchant ship. But in a fleet battle or an assault on a fortress, it could still prove devastatingly effective.
The Canticle class had now been in service for ten years. Apparently, the Alliance had designed it specifically to deal with the Empire's Skyforts. With the mindset that if the enemy had something, they needed it too—and if the enemy had it, they needed something better—the Empire had also been working on an arsenal ship of the same type, the so-called Martial Guard class.