To the day he died, Donald Locklear would not be able to properly explain what he felt that day. Looking down on the capsized form of USS Utah, as flak fire began to burst from the ruined hull. Impossible flak fire.
From an impossible figure.
Wait a second...
"Look, Locklear, it's clearly not an impossible figure, given Utah's walking around right over there examining the unconscious California." The wing commander was trying very hard to not look over at the figure of the sunken battleship, which was unconscious and had half her torso and head blown off with brains showing, probably representing that magazine detonation. Any human would be very dead from that, but since ships could be rebuilt from scraps...
"Sir, it's not possible to have a waist that thin with curves that big, without absurd corset shenanigans." Locklear gestured in front of his chest and behind his rear end for emphasis.
"...I really hope you don't put that in your memoirs."
"If I live to write memoirs, sir, I'd be grateful enough to God that I'd never properly explain why the hell I thought that."
"Thinking with the wrong head, son. It happens to all of us when we're young, too often in my opinion..."
in the future, Thomspon will be on board inside Sara?
Yes.
Yamato: *Blushes* She was on my deck when she captured me...
You are lying, Yamato, she clearly got deeper into you than that.
More precisely I believe Abyssals, as far as Sky's works and BelBat goes, are realizations of the desires of the souls of all the civilians and soldiers who died because of the machinations of a few. To put it more simply: Abyssals are the end result of the negative emotions given physical form. Though this wouldn't just cover only soldiers; it would also include civilians as well and given the time period..... yeah, there's bound to be literal tens of millions angry ghosts before the war is even over.
By your analysis, most of the Abyssals CAME FROM CHINA, NOT the Soviet Union, because the USSR's war was almost purely a land war, while China's enemy since the Century of Humiliation began was
always from the sea. And before we get into Nationalist vs Communist, the angry ghosts are more likely to laugh themselves to second death by seeing how capitalist the Chinese are and how far they are from what communism is on paper, than they are likely to be angry about it.
Even if the Chinese are coexisting with the Abyssals in a Mexican Standoff (a sufficient number of nukes vs. Abyssal firepower/defence concentration) their reaction to the Japanese being besieged is probably "Guess you should have hanged way more war criminals to satisfy the vengeance of everyone you attacked... though we can't complain about Ishii's death, because that was slow and drawn-out enough for anyone."
It is far more likely that the Abyssals don't bother the old defenders nearly as much as the old aggressors, other than relatively minor things like taking over Singapore and Hawaii. So most countries defend their border from occasional raids by rouge bands, and that's it.
By Belated Battleships methods, Africa, South America, India, Australia, hell even Russia and the Middle East are MORE screwed than China by not having enough navy for their coastlines.
Hence why I strongly advise taking YOUR idea and running with it in this fic, instead of falling into the BB fanon mold that most Kantai Collection fanfics adopt as canon.
In case I haven't been clear enough yet: Based on sound logic, reason and geography, I submit one (1) vote for Abyssals being "angry ghosts" which mainly target the aggressor nations of WWII, with some exceptions (Japanese angry ghosts would want to take the Marianas, Iwo Jima and Okinawa to prevent another repeat of Starvation, but the humans see this as Abyssal conquests).