In episode 2 of the anime Shin takes out a column of heavily armored Lowes singlehandedly by firing into the roof of their turrets. It's an excellent an example of Truth in Television as real world tanks have weaker armor on their turret roofs. This tactic was notably used in the famous defense of Pavlov's House during the Battle of Stalingrad, where an anti tank rifle positioned in the upper floor of the house took out a dozen German tanks by firing down into their weaker top armor.
Lena seems to be subject to a great deal of misogyny in the Republic military, with a number of characters outright telling her that she should focus on finding a husband rather than pursuing a career in the military. The fact that San Magnolia is so misogynist shouldn't come as too much of a surprise, because racist societies have historically tended to favor "traditional" gender roles. This can even be seen in their female military uniforms, which differ drastically from their male counterparts and seem almost designed to "show off" the female figure. This is in contrast to the military uniforms of other nations, which show little to no variation for different genders.
The Legion seems content to only launch small probing attacks against the Republic's defenses. This is because the Legion is fighting a war on multiple fronts, so the majority of their forces are committed elsewhere. These small attacks are only designed to cause attrition and lull the Republic into a false sense of security. They were also probably waiting for the supply of 86ers to run out, ensuring that the Republic had no reserves when the Legion launched their final attack.
Given that No Face might actually be Vaclav Milizé, he might have known how the Albas will act and that information was shared with the rest of the Legion. It's no coincidence that the Legion invaded San Magnolia when the Albas were having their festival.
The anime includes a scene where Spearhead finds a crippled Löwe in an abandoned zoo during their trek through Legion territory. After dispatching it they immediately start speculating if other countries besides the Republic have survived. After all, they found the Löwe far outside of Republic territory with fresh battle damage. The nature of the damage was also another major clue, as the Löwe was penetrated in its frontal armor, which is far too thick for a Juggernaut's 57 mm gun to penetrate. On the other hand a Federacy Vanagandr can easily do that kind of damage with its 120 mm armament.
The forces under Lena's command manage to hold off the Legion for two months following the fall of the Grand Mur despite having little to no support and being heavily outnumbered. One reason why they lasted so long was because most of the fighting took place in urban areas, which are one of the few types of terrain Juggernauts actually have an advantage in. This allowed them to employ their preferred tactics of strategic choke points and ambushes, which negated much of the Legion's numerical superiority.
Despite this the initial defense of the Republic's capitol does not appear to have gone well judging by the end of episode 17. This is likely, because the city's wide boulevards made it very easy for the Legion to bring in heavier units like the Löwe and Dinosauria. The latter unit in particular is virtually impervious to the Juggernaut's 57mm gun, which likely explains why a couple of them broke right through to Lena's HQ during the battle.
The anime-original scene from episode 2, in which Lena rants to a class at the San Magnolian military academy about the truth behind the "unmanned" Juggernaut units, has been criticized for having a tone at odds with the rest of the series. However, there is one way in which this scene reinforces the story's themes. In a later scene, Annette and Lena are discussing her outburst, and Annette wonders if Lena is going to get in trouble for it. Lena replies, cheerfully and confidently, that her close connection with the ranking officer Jerome Karlstahl will protect her from any repercussions. This serves as a subtle introduction to an aspect of Lena's character that will be made more explicit during a conversation between Lena and Karlstahl in episode 4: that it's been easy for her to be progressive and say subversive things because there have been no real consequences for that behavior, just like how it was easy for her father to have them fly beyond the front lines during that ill-fated helicopter ride, because subconsciously he didn't believe that non-86s could die on the battlefield. In other words, it's easy to be "brave" when your actions don't put you in any real danger.
Lena dying a streak of her hair red after Spearhead Squadron is sent on their suicide mission isn't just to honor their memory. It also serves as a not so subtle middle finger to the Republic's racist society. Pure white hair is seen as sign of racial superiority by the Albas, so by dying her hair Lena is showing solidarity with the mistreated Colorata. Furthermore this act proves just how utterly moronic the Albas' racism is by showing that a bit of hair dye is all that really separates them from their supposed racial inferiors.
The fact that Lena develops a crush on Shin long before she actually meets him in person shouldn't come as much of a surprise. After all Lena is essentially a social pariah in Alba society due to her outspoken views, with no male friends to speak of. So her conversations with Shin are likely the first significant social interaction she's had with a guy her age. It's only natural that a lonely young girl like Lena would soon begin to view him in a romantic light. It also helps that the Para-RAID transmits emotions, not just sound, so she can tell the much-feared Reaper is a lot more human and warmer than how he presents himself.
In Volume 5, when Lena goes to Vika to ask him more questions about the nature of extrasensory perceptions (specifically, Shin's ability to hear the dead), Vika calls up Lerche and tells her to bring Shiden into his room, and also has her leave the door open until she returns. Shiden is a bit irritated to have been summoned so abruptly, but Vika doesn't really explain himself. The narrative doesn't spell this out, but he's clearly concerned about Lena as a young woman meeting him alone late at night, so he refuses to speak with Lena until another woman is present to pre-empt any rumors/accusations of sexual harassment or scandal. The fact that this scene was in a volume that was originally published in October 2018, at the height of the #MeToo movement's global influence, was likely no coincidence.
In Volume 8, the Phönix becoming a mass-produced unit makes sense because the only Legion commander who treated it as a disposable unique prototype was the Merciless Queen. Since she is currently in Federation custody, her opinions no longer have any bearings on Legion doctrine, and other Legion commanders like No Face would likely prioritize making the Phönix a regular unit to manufacture and send to the battlefield.
The Spearhead Squadron not going out on daily patrols despite such patrols potentially providing valuable information on the Legion's movements makes a lot of sense when you realize that Shin, the captain of the Spearhead Squadron, can hear when the Legion are close. So if the Legion aren't anywhere close to the Spearhead Squadron's area, that means a patrol would be a pointless waste of time and fuel. So Shin just has his team stay at their base most days and lets them try to have some semblance of a peaceful life when the Legion isn't close by. It also gives their mechanic more time to properly maintain the Juggernauts, which could help explain their high performance in combat.
San Magnolia's use of FN FAL-like battle rifles as their standard issue shows how utterly unprepared for war they are: battle rifles use full-powered cartridges, making them powerful but extremely hard to control in automatic fire, a factor that in real life led to the US and allies developing and adopting less powerful but more controllable assault rifles as soon as they were actually used in combat. While battle rifles still have their uses, armies with actual combat experience tend to replace them in general use, as Giad did here... But San Magnolia still uses battle rifles years after the start of the war with the Legion.
Shin's practice of performing a Mercy Kill on any badly wounded 86er is likely done out of necessity, as their unit has no doctors or medical facilities to treat them. Therefore any serious injury is pretty much a death sentence. Plus shooting them in the head prevents the Legion from harvesting their brain.
San Magnolia might have actually won the war against the Legion if they hadn't decided to use the 86 as canon fodder. Their racially motivated incompetence resulted in them throwing away every military advantage they had. These included a communications system immune to Legion electronic warfare and the means to mass produce advanced mecha. Rather than use these to their tactical advantage they instead focused on getting the 86 killed in droves by sending them out in walking death traps. Meanwhile their state of the art command and control system was more often than not run by drunken idiots. The success of other countries in taking back territory from the Legion shows that San Magnolia could have turned the tide against the Legion if they'd committed their whole society to the war effort. Instead their obsession with racial purity resulted in millions of unnecessary deaths and likely lengthened the war by a considerable amount.
The treatment of the 86 is so bad that 86 converted into Shepherds view their assimilation by the Legion as an improvement. These individuals on some level seem willing to work for the Legion if it means getting revenge on San Magnolia and "liberating" their compatriots in the most twisted way possible.
Veteran 86 are sent on "scouting missions" deep into enemy lines at the end of their five year terms in order to dispose of them. Given that the Legion has been shown to prioritize capturing highly skilled individuals for conversion into Shepherds, the Republic has basically been handing talented commanders to the Legion on a silver platter. This is commented on during a meeting between the Federal Republic of Giad, the United Kingdom of Roa Gracia and the Alliance of Wald and later emphasized when it is revealed that most Black Sheep and Shepherds including the Supreme Commander directing the massive offensive in Volumes 2 and 3 were former Republic citizens.
Shin and his family were arrested and placed in an internment camp in San Magnolia as part of the general policy of rounding up all non-Albans. But the truth is, the Nouzen family was one of the few 86'ers the San Magnolian government would have been fully justified in arresting due to Shin's parents having emigrated from Giad to San Magnolia under suspicious circumstances, and the Nouzen clan being a very powerful family in the Giad Empire to the point that Shin's distant relative, Kiriya Nouzen, was high up enough in the ranks that he was a bodyguard for the Giadian royal family, and one of Shin's grandfathers was even part of the Giadian Senate. Simply put, the Nouzen family's circumstances happened to fit a lot of the suspicions when it came to San Magnolia's propaganda that the 86 were Giadian loyalists who performed sabotage operations in the war's opening days. It's safe to say that he and his family would probably have been detained even if they lived in a more tolerant country like Roa Garcia or Wald due to their blood connection to the aggressor country's leadership.
The parallel between the Sirins and the 86, especially during the former's death march. Throughout the entirety of the 5th Volume, the 86 had all been leery of them due to how uncanny they were, but when they had to literally walk over the mountain of corpses made of Lerchen's kin, it became all too clear it was partly because they were on the same path as they had no future before and had done the same thing in order to survive until that point.
Sirins are made using the brain scans of mortally wounded soldiers in an effort to preserve Roa Gracia's manpower. It's also mentioned that Sirins currently make up half of the United Kingdom's military. Which makes one wonder just how bad the United Kingdom's casualties have been when half their military is made up of the cybernetic ghosts of dead soldiers.
Volume 8 implies the Legion has probably completely overrun many smaller, less defensible countries. After 10 years of non stop war only countries with large militaries or strong natural defenses have been able to survive. Therefore it is disturbingly likely that a significant fraction of the world's population has already been completely exterminated by the Legion. So even if humanity eventually prevails against the Legion there will likely be many countries that have simply ceased to exist by the time the war is over.
Essentially confirmed in Volume 9: an isolated and small country like Noiryanaruse is on its last legs after spending 11 years fighting the Legion, almost the entire adult population has been killed, its armies are a fraction of what they once were, and their Feldreß models are being held together with metaphorical chewing gum and duct tape. The only thing that keeps the Noiyanaruseans fighting is their insanely fanatical religious faith.
