The Three Great Academies of Kivotos (Trinity, Gehenna, and Millennium):
A majority of playable students released come from these schools compared to every other school—even if the Cast Herds aren't directly proportional to the actual total amount of students their respective schools have, it would reflect how much influence they have over Kivotos that Sensei would get involved in their matters most often, leading to the number of students they interact with.
They also share a thematic motif. We know that Trinity and Gehenna represent Heaven and Hell respectively, but why is Millennium grouped with them thematically? From it having mainly students with human only traits as well as a focus on the sciences and logic. This would logically mean that Millennium represents Earth or the Physical World.
While the Reasons for these three schools having a large influence is explained as Trinity and Gehenna’s long running history and Millennium’s ground breaking innovations, they do have a thematic reason. Due to Blue Archive borrowing many motifs from Christianity, a religion with a long history and influence. It would make sense that the main Academies would share these traits alongside being Heaven, Earth, and Hell; the three main worlds in Christianity.
If one considers Gematria's explanation about Mystics, being that they are essentially phenomena no one can explain within the boundaries of science or common sense, then it can be seen as why some student EX Skills can range from supernaturally powered shots and bullet-resistant durability to weirder ones like students powering up from just eating in seconds, a sports bottle exploding, lazing around somehow boosting attack power, and dropping cover and a giant blob of mint ice cream out of the sky.
The armor types for mooks make sense in-universe; those wearing Light Armor are mostly students, who can rely on their near immunity to bullets to wear casual clothes instead of cumbersome armor; those in Heavy Armor are robotic or vehicles in nature; and those in Special Armor outright aren't conventional flesh-and-blood beings, including Mimesis.
The Schale's Happy Valentine Patrol event has nearly 20 students that grant bonuses for every one of the four currencies you can gather, which by comparison is much more than what you'd see in any other event. Why, because it's Valentine's Day! Where most events focus on a specific group of people, this is city-wide, and adding to that is you scheduling meetups with any student.
To be fair the power of Sensei is true and real. Have you ever seen how unoptimized they fight on auto? Tactical Challenge is the place to witness such horrors of how students not getting instructions from Sensei directly dramatically changes outcomes of fights from wins into constant losses on their own.
The Foreclosure Task Force:
One factor how the small group of five students could contend with their enemies in Volume 1, even before Sensei came, is because their attack types are suited for the job: Shiroko and Serika are Explosive-type for the Light-armored Helmet Gang and Prefect Team, while Nonomi and Hoshino are Piercing-type for Kaiser PMC.
The members' stars reflect their underdog situation to varying degrees. Hoshino is a 3★, which makes sense because she's not only the club head but also an experienced lone wolf, while the other members are 2★ to reflect the relative lack of experience but not 1★ since they have to make up for the lack of numbers and resources... except Shiroko is curiously a 3★; this isn't just because she's the most physically fit, but it also stems from her time as a lone wolf like Hoshino prior to joining the FTF.
The star rating for the members correlate with their in-universe ranks; Aru is the Boss (3★), Kayoko is the Department Head (2★), Mutsuki is Staff Chief (2★), and Haruka is an entry-level employee (1★).
There's a reason all Arius Mimesis Mooks and the Arius Squad (except Hiyori who uses Light Armor) use Special-type Armor; students with effective Mystic-type attacks are a rarity amongst Gehenna and Trinity, let alone the entire playable cast. It's a sign of how prepared Arius was to fight, including the default Hina, whose Explosive-type attacks are resisted by Special Armor.
Therefore, to combat the onslaught of Special Armored enemies, almost all of Trinity's known members of Justice Task Force and Make-Up Work Club employed Mystic attacks when having their alternative outfits (mainly swimsuits), with Hifumi and Hanako being an exception, even then, the former one deploys a powerful yet costly tank onto battlefield, and the latter has Sonic attacks with large area coverage, which are moderately effective against Special Armor. From Gehenna's side, Mutsuki uses Mystic attacks to cover very large area and Kayoko's New Year version became one that significantly boosts Mystic damage dealt against Special Armor.
The Arius Squad:
Playable students Azusa and Saori fire single shots with their assault rifles. After all, Saori was the one who taught Azusa ever since they were kids.
All playable squad members, including former member Azusa (default version), deal Explosive damage. This informs Arius's preparations against Trinity and Gehenna, because the majority of students from those schools wear Light (which is weak to Explosive) and Heavy Armor (takes normal damage from Explosive).
Azusa's default and summer versions favor Indoor Warfare greatly, just as the Arius Squad do. Not only is this because they all favor guerilla tactics, which is advantageous in enclosed environments, but it's also a consequence of living in the dark, confining, and underground Arius district (supported by their favorability for Urban and Field Warfare graded 'Neutral' and 'Terrible' respectively). Azusa (Summer) is the only subversion where her Urban and Field favorability both become 'Bad', likely reflecting her becoming used to living on the surface while being quite embarassed to show herself in public in swimsuit.
It's a pain for players that the Arius Squad is only effective when its members are together, making it difficult to integrate them into other squads, but this has in-story justifications: 1) Due to their harsh background, the Arius Squad spent years on their own as a tight-knit group cut off from contact with any outsiders, and even after escaping from Arius in Vol. 3 Chp. 4, who could they trust not to report them to the authorities, let alone stick around students they antagonized? And 2) they've been trained by Saori and act as a single unit for so long that having anyone else in their team is likely to muck up their tactics.
It makes sense that Arius Squad is suited for Hieronymus in gameplay; their archenemy is Trinity, a religious institution practicing religion, crosses and the like, and Hieronymus is an Angelic Abomination fought in a church. They could not have picked a more fitting enemy.
Funnily enough, they’re a part of the group who take on the Chroma version of Hieronymus, right alongside members of Trinity in the Sisterhood and the Remedial Knights in Volume F.
In Volume 3, Chapter 4, Mika says she dislikes the hymn, Kyrie eleison, for its repeating verses of “Have mercy upon us” as well as skepticism over if there’s a higher being above her. While this could be seen as Mika being bored with the classes and song, she does also have a deeper meaning for her dislike of the song. Kyrie eleison or Lord have Mercy, is a real Christian hymn about begging for forgiveness from God and Jesus. Throughout the chapter, Mika still feels incredibly guilty for all she had done. When Sensei meets her after she’s finished it for classes, she says “it looks weak to ask for pity”, showing early on she feels unworthy of forgiveness. This comes to a head in the Arius chapel, where after saying her unworthiness of mercy and praying for Arius Squad’s mercy, a broken gramophone suddenly starts playingKyrie eleison, as if something wanted to tell Mika she’s worthy of mercy.
RABBIT Squad setting up their protest in Kousagi Park, which itself is located in a nearly abandoned part of the D.U.; if they wanted to stage a protest, it would've made more sense to do it somewhere they can be easily heard like the more populated areas. The most likely reason for this is to avoid civilians from getting caught in any conflicts like the fight between them and Valkyrie, that even with SRT going under, it's still an organization for the people. V4C2 supports this with Miyako immediately going against Kaya and FOX Squad's plan to blow up Kousagi, protesting it would have reaped civilian casualties.
The matchups between student teams and Chroma-tized raid bosses in the story and gameplay of Nisir's Summit make sense:
Binah is tearing up Abydos's own turf, so of course the Foreclosure Task Force (sans Shiroko) would defend their home, and Problem Solver 68 is willing to help on account of their friendship. In gameplay, Serika, Aru, Mutsuki, and Haruka use Explosive ammo effective against Binah's Light Armor. (Maki, popular for the normal Binah's raids, has an honorary appearance in the battle.)
Chesed sends out swarms of robots that need Herd Hitting Attacks, except every single student sent there initially only have EX Skills that work on single targets and don't have Mystic attacks to counter the Special-armored enemies, and while Tsurugi's EX changes her normal attacks to spread in an area, she's still Piercing-type and only one fighter, thus bogging down their progress. Then Red Winter comes in, where Cherino's EX Skill comes in handy against crowds, and her underlings help a lot.
Shiro and Kuro are singular targets, perfect for Miyu's weakening EX Skill and Miyako's for some damage. It's concerning that there aren't any safeguards against boss attacks, but who needs them when you've got firepower to end things quickly in the form of Hina, Aris, and Yuzu remote-controlling Avant Guard?
A popular, if very niche team against Hieronymus is the Arius Squad, who not only have the right EX Skills for the fight (Hieronymus (Chroma)'s armor type has been changed to Special, making Explosive attacks less effective now), they were raised to tear down religious symbols, specifically Trinity. Arius fighting alongside Trinity students though is itself a symbol that the schools are burying the hatchet, or at least starting to.
Hod has several examples:
Veritas's hackers have Crowd Control EX Skills, one of whom is Chihiro's, who finds an effective niche in Hod's normal raids (unfortunately, Chroma-tized Hod has Special Armor). Another is Hare, who can inflict hers on both Hod and the tower in front of it.
For Seminar, Yuuka's I.F.F. skill is single-target, Noa's Speedy Record-Keeper and Found an Opening! are both dedicated to single targets too, and Koyuki's area attacks can be helpful when dealing damage to both Hod and its tower with her potent Mystic attacks.
With all the support being taken care of by other students, Megu and her clubmates provide the massive "onsen development" (firepower) needed. Megu herself also gains Crowd Control application just for this specific battle (her normal attacks increase the CC gauge).
Perorodzilla's Armor has changed to Light, but the usual tactics for it still apply: attacks to hit its multiple minions and single-target ones for the boss. Most of the Make-Up Work Club (Hifumi and Azusa ironically meeting Perorodzilla like they wanted) and the Gourmet Research Society (having helped them in Volume 3) have such Skills for this, with Akari, Izumi and Azusa all now effective. Oh, and Fuuka and Juri are there too, though the gourmets likely kidnapped them as usual.
Shiroko giving her ski mask to Kuroko makes sense on a personal level.
Shiroko greatly enjoys bank heisting, if at least making plans for them just as much. After no longer needing to carry out the Chroma’s invasion, Kuroko can finally be allowed—as much as she feels like she can—enjoy her hobbies once more, and Shiroko is giving her the push to go do so by giving the mask.
There’s more reasons why Shiroko doesn’t give her scarf to Kuroko; other than having to replace Shiroko’s model to not have the scarf in-game after that point if she did, it was given to her by Hoshino, whom, along with the other members of the Foreclosure Task Force, Kuroko likely won’t go see anytime soon after all the trauma she went through, so as much as she’d appreciate it, Kuroko may not be keen to have a reminder of those she lost…
