Wild Mass Guessing for Wave Motion...Space Battleship Yamato 2199:
Many of the new characters will die in the battle against Domel.
Celestella will die seeking revenge for Mirenel.
Wolf Fraken will become Harlock, for one continuity.
Mamoru Kodai will become Harlock, just like in the manga of the original seriesAnd when this is found out, the Gamilas surrender unconditionally.
The Cosmo Force reverse engineered captured Gamilas technologyMore specifically, what would become the Wave Motion Gun, shock cannon and wave motion shield (that they couldn't make work correctly without Starsha's core, having only huge shock cannons), a sublight-only version of the wave motion engine, and, most evidently, pre-Yamato energy weapons (just confront the turret of the Yukikaze◊, so distinctive that it's enough to allow medical personnel to identify its model from an unspecified but otherwise similar class of destroyers, and the Kirishima◊, with the most widely used type on Gamilas ships◊.
We know that the Cosmo Force stopped the Gamilas twice at Mars before the invaders switched tactics to raids and planetary bombs (Yuki openly states the victory of the First Battle of Mars in the first episode, with the background image implying it was a costly victory, and Okita is often called the Hero of the Second Battle of Mars, implying another but very close victory), and that the Cosmo Force still uses more traditional firearms and missiles, devastating but with very short range, so they had some wreckage to study. Nothing easier that Cosmo Force, after an hard-won battle and one where they had nearly been conquered, decided to reverse-engineer the enemy technologies to being able to hit them at range (something that didn't work really well due the enemy having Deflector Shields), closing range faster (something that did work due either the Gamilas shields offering imperfect protection against solid objects or the shells being just that powerful), defending from enemy firepower with the wave motion shield (failed due the lack of reactors powerful enough) and fielding more powerful weapons (the shock cannon, that, without sufficiently powerful reactors, could be mounted only on battleships and only one per ship, with inadequate cooling technology preventing it and its support systems from being miniaturized enough for turret mounts).
Then, when Earth was about to either surrender or launch an escape mission, Yurisha showed up with the plans for a proper wave motion engine, with its support systems enabling to miniaturize the shock cannon to mount it on turrets (and human mind developing the Wave Motion Gun), and Sasha provided the core to make the thing work...
At the end of the series the Yamato will be welcomed home by a few surprise shipsNamely this◊, a couple of these◊ and a small squadron of these◊, with the Andromeda being laid up.
If the series gets a second season, Serizawa will be executed for war crimesBecause after the defeat of the White Comet Dessler would show up with his fleet, point out that there's no peace treaty with Gamilas and threaten to resume retaliation for the unprovoked attack at first contact, with things evolving in a formal peace with Gamilas giving symbolic reparations for the bombing on Earth and Serizawa given to Dessler to pay for his crimes. And get executed after a completely regular trial.
Yamato was not the first choice for the voyage to IskandarIzumo was, repurposed after Yurisha brought the plans for the warp engine, but was destroyed during construction by a Gamilas raid specifically targeted at her.
After the loss of Izumo, seven ships were laid up in hidden locations, equipped with shock cannons and wave motion engines: Arizona by the US, Bismarck by the European Union (with protests from France, UK and Italy for the name: France because it's the name of a German ship, UK because they have a more glorious naval history, and Italy because the logic of naming the ship after Europe's mightiest battleship falls before the superior firepower of the four Littorio-class battleships, but the name stuck because of the battleship Bismarck's fame and the British alternative name, Prince of Wales, being that of a ship with a lackluster record), Borodino by Russia, Huáscar by South America, three unnamed warships by China, India and Africa (their naval history had less glorious names to choose from) and Yamato by Japan under the relic of the old battleship.
Due to shortages in resources for the other ships and works on the Yamato having been slowed down due a sudden redesign, it looked like the choice would fall on either Arizona or Borodino as they would be completed first, but then Serizawa produced the plans for the wave motion gun that the Yamato had just been redesigned for, and, being the only ship that could be completed with it in time for Sasha's arrival with the wave motion core, the Japanese vessel was ultimately selected.\\ In the end the other battleships were completed after the Yamato left for her voyage, with cores copied from Sasha's one and redesigned with wave motion guns. And the rest of Europe laughing at the Brits when India named their ship Prince of Wales (a battleship with that name had been sunk while defending them, after all). And the Chinese battleship, completed with Japanese assistance (the price being putting a Japanese captain on her), was the Andromeda.
The White Comet Empire is indirectly responsible for the devastation of EarthBecause their continued attempts at invading the local galaxy cluster keep most of the non-garrison Gamilas fleet busy in the Lesser Magellanic Cloud, and when the war against Earth started they just didn't have the forces to spare to wipe out Earth's fleet in five minutes, show up in orbit and demand a surrender.
Had Starsha not sent the plans for the wave motion engine or the Yamato got destroyed before leaving, Humanity would have been saved anywayBy either surrender after losing the last hope or invasion and quick conquest. In both cases the Gamilans would have either restored Earth or shipped Earth's population to another inhabitable planet, whichever better suited Dessler.
Kaoru's life will be in extreme danger when the Yamato returns to Earth.For the rest of the crew, returning to Earth means a heroes' welcome. But Kaoru Niimi is at this point the only person left alive in the crew who has first hand knowledge of General Serizawa's plan and orders behind the mutiny. Serizawa's involvement in starting the war may have been hushed up in the name of solidarity and public morale but if he were linked to an attempt to derail the Iscandar mission, then his career; at very least would be destroyed. The Iron Tiger has not gotten where he is without a strong degree of ruthlessness and sacrificing one woman's life to ensure his survival would be a price he would be quite willing to pay.
The Gamilas originally came to Earth to share the later albums from their greatest band in history, known on Earth as the CrescendollsAnd they became militaristic and started conquering other worlds in the first place precisely to prevent others from kidnapping them again.
Type 3 rounds usually have nuclear warheadsWith most of the Yamato's crew not knowing it due Japan's Nuclear Weapons Taboo. Magnificent Bastard persona he has for most of the show. This is because he actually engineered the rebellions and his subsequent attempt to destroy the Yamato at the cost of his homeworld specifically so that the corrupt members of High Command would be outed/killed and the others would have a chance to set up a stable empire.
In this theory, Dessler first became aware of the problems inherent in his empire when he discovered Cerestella and Mirenel imprisoned simply for being Jirel on Leptapoda. The moment immediately after when he rescues them out of pure compassion is a hint to how he honestly wants to help but is repeatedly stymied by selfish officers such as Gimleh and Zoellik.
Dessler then began carefully setting up a large-scale revolution, allowing Gimleh and the Imperial Guard just enough leash to cause widespread misery with minimal losses of life to encite discontent into the populace. He also widely distributed the Gamirroids across the various theaters so that they would be the first obstacle for any revolutionaries and making it easier for them to defeat the androids.
However, when this went on for several years with no sign of the political climate being right for a rebellion, Dessler finally had his soldiers begin to Planet Bomb Earth, knowing that Starsha would be unable to simply stand by and allow the Earthlings to die off. Since the previous encounters with the Earthlings proved they were stubborn enough to have a fighting chance at making it to Iscandar, he knew that they would provide an excellent beacon of hope for the downtrodden civilians and prod them into a full civil war.
Likewise, Okita's Take a Third Option manuever in Episode 8 was anticipated by Dessler and intentionally left open, since he knew the Yamato had a Wave Motion Gun thanks to the Floating Continent's destruction. After they successfully escaped, he recalled Domel, since he was a known entity and if the Yamato simply survived an encounter with him, the effect it would have on the rebels would be momentous. When Gimleh brought the fact of a planetary rebellion to his attention, Dessler intentionally allowed him free rein to deal wih the threat, aware that Gimleh's reaction would be far too extreme and only encite further revolution. In Episode 10, Dessler had the Yamato's course plotted and sent Captain Lang to wait for them in the dimensional rift he knew they would fall prey to. He also briefed Melda Ditz prior to the rendezvous, telling her to remain honorable and courteous, if a bit brusque, and also to reveal the truth of the war's beginning to make the crew more willing to assist the Yamato. The Imperial Guard officer aboard, not having been informed of the situation, almost caused the plan to collapse, but Lang managed to capture him in time and reinstate the tow cable and the Yamato's trust in the Gamillan crew. While Melda was trapped on the Yamato, Hoshino approached her, thinking that an alliance would be the best move under these circumstances, and also seeing that Melda was intentionally building up the crew's trust and tolerance of Gamillans in general in preparaton for later. Melda, realizing the opportunity she had been given, recruited him into the plan and put him in contact with Dessler.
Dessler also allowed Zoellik's scheme to go forth because he knew it would only further the perception of the corrupt High Command that was beginning to circulate amongst the people; as well, he needed time to put the next phase of his plan into motion and cause Domel to be recalled at a critical time and Ditz be sent off to Leptapoda to be used as a figurehead for the resistance. Hoshino then sabotaged the OMCS, forcing the Yamato to head to Beemela, where Dessler was replacing the data already in the Wave Motion Core with information on how to access the warp gate network. (This is why the rest of the temple-like area is covered by a thick layer of dust, while the Core appears brand new.)
Okita's destruction of the warp gate network meant that the Yamato would not have to face another overwhelming threat like Domel's attack in Episode 15 for the remainder of their voyage, the empire solely reliant on the Imperial Guard fleets for defense. In Episode 20, Hoshino placed Yuki in position before stopping the Zaltzi commando team and alerting Yuki to the position of the boarders, so their time aboard the ship would be minimized. While he was aware that Yuki was not truly an Iscandarian, since Yurisha was in a coma and could easily break her possession of Yuria (not to mention the fact that Hoshino did not want Yuria to be put in danger like that), it was far easier of them to simply capture Yuki in her stead. Immediately after, he carefully nudged the Yamato into reconning Leptapoda for repair supplies, just as Frakken (who is also in on the plan) arranges for a brief layover there and Melda arrives to begin the prison riot. This victory galvanized the resistance into taking action, and the meeting between the Yamato and Ditz's allies allows Melda to be put into position to assist the Yamato. As they began the final stage of the path to Iscandar, Melda and Hoshino briefed Okita on a small segment of their plans, which is why Okita heads directly for Gamilas immediately after informing the crew that it is Iscandar which is their main goal.
At the beginning of Episode 23, Dessler intentionally misses the Yamato to test the power of his Dessler Cannon on the planet behind them. His abandonment of the capital and subsequent Colony Drop were intended to trigger a Moral Event Horizon for the "loyalists" and firmly alienate him, and his government, by proxy, from the people. Okita, as instructed, fires on and destroys the falling portion of New Baleras, both to firmly paint the Yamato's crew as paragons of virtue in the people's eyes and ensure Starsha will still give them the Cosmo Reverse System. Dessler then begins quietly recalibrating the Dessler Cannon so that the beam will only destroy the palace and nothing else, killing off the majority of High Command in one fell swoop and allowing Ditz to step into the power vacuum and repair the empire; Melda has given the Yamato an upgraded version of the Wave Motion Shields which will allow them to survive the blast "miraculously." The plan is for Norran to get Yuki out of the fortress and to minimum safe distance and then trigger the overload after Dessler has fired, but he pulls the trigger early to save those still in the palace.
After Dessler warped away from the exploding fortress, he had Goer chase the Yamato into the gate, and seperately told Frakken to defend the Yamato and then kill Goer in the name of Ditz's government. This is where the plan starts to unravel. Dessler's plan is to use the androids to invade the Yamato, knowing thanks to information provided by Hoshino that the Yamato's crew knows how to create a virus to shut down the androids due to their research on Alter. During the attack, Dessler was to go over to the Yamato and attempt to kill Okita, being stymied en route and forced to return his ship when the androids went down. Desperate, he was to destroy his ship by firing the Dessler Cannon and thus destroy the final link to the old government of Gamilas. However, Cerestella's unanticipated presence aboard the Yamato caused her to accidentally release a wave of psychic energy that startled Dessler into shooting her. After realizing he has just unintentionally killed the same person he rescued from Leptapoda years ago, he goes into a Heroic BSOD. Cerestella, on the other hand, has learned of Dessler's plan thanks to her brief mental uplink with him and shoots him both to snap him out of it and provide the impetus for him to return to his ship before turning the gun on herself so she can be uplinked to the Cosmo Reverse System in order to save Dessler's life after he uses the Dessler Cannon to destroy his ship. When both she and Yuki are seemingly killed by his bodyguards' fire, he stops them from shooting on Kodai when he tries to kill Dessler, because he wants to keep from killing as many people as possible. Likewise, when he threatens Velte Talan at gunpoint later, the intent is to break Velte's loyalty and allow him to abandon ship, which fails as all except him are killed in the subsequent explosion and Dessler then pulls the trigger, accomplishing his goal of providing salvation for the universe, in that he is removing the poisonous influence of the Gamilas High Command and himself from the cosmos. However, Cerestella uses the Cosmo Reverse System to preserve his life, which is the source of the blue smoke cloud surrounding the Yamato as it emerges from the warp gate.
If this is right, the upcoming "Voyage of Recollections" compilation movie will be a chronicle of the above events, ending with Zordar and his soldiers retrieving Dessler from the warp corridor, believing that Dessler will desire revenge against both the Yamato and the rebellion and will be perfectly willing to ally with them.