fitting into the gh2 story
Okay, before starting this long-ass explanation, it might be good to give a little backstory.
It seems like there's always been friction between the board of directors and the chairman/director of Bell Liberty. Back in GH1, the board was divided into two major factions - one that supported the director, and one that opposed him. The assistant director (Kuganuma) was the head of the opposing faction, and he was a platinum-class douchebag. He had the board meet and vote to expel Keita from the school while Kazuki was away just to be a dick to Kazuki.
I think that making Sakaki the assistant director in GH2 is supposed to make the player predisposed to not liking him, and that info is kept secret until he calls the assembly to announce the school closing. So the player is hit with two punches at once - the problem of the school closing and ARGH another asshole assistant director?!
It goes a little deeper in GH2 because a bunch of "outsiders" are on the Bell Liberty board now (I'm assuming the board was all Suzubishi peeps back in GH1 because that just makes sense) but now it's being taken over by the Sakaki group. Well, that's all below so I'll just get right to it!
the "secret" story of gh2
To get the full story of what's going on at the school, you must play these routes:
Tomo, Joker, Sonoda (unlocked by completing Tomo & Joker), Sakaki (unlocked by completing Sonoda)
Buckle your seatbelts, this is a long and complex tale of how adults are assholes who cannot be trusted.
Okay, the first thing you need to know is that the Suzubishi group is a conglomerate of loosely related companies. The business types mentioned in GH2 (and the ones that are relevant to the story) are private school management and pharmaceuticals. (They also do everything else from sports to appliances to cosmetics, etc, but that's not relevant here.) There is a rival group that also has businesses in these two industries, the Sakaki group.
You can already see where this is going, right?
In recent years, the Sakaki group hasn't been doing very well, and they ended up somewhat grudgingly forming a partnership with Suzubishi. Sakaki pharma has a bunch of "bad debt" (whatever that means in business terms) and accepted assistance from Suzubishi so they could continue funding research for their next big drug. The Sakaki group also got involved in the board of directors at Bell Liberty, and has slowly been increasing its influence over the school and kind of taking over the board.
The first person from Sakaki to join the BL school board was our very own badass math teacher, Sakaki Sojiro, the younger brother of the Sakaki pharma president, Sakaki Yuichiro. That was a bit more than two years before the start of GH2, and he was given the position of assistant director of Bell Liberty. Since the current school year is his third at BL, that means he started when the current third years were just entering school. (PS: Let's call the hot prof Professor Sakaki from now on so this doesn't get any more confusing than it already is.) Professor Sakaki had already been teaching math at a high school owned by his parents, a profession they didn't approve of, but tolerated since he was an otherwise obedient son.
BY THE WAY, Professor Sakaki's father is the head of the Sakaki group. This isn't super clear in the game (either that or I'm stupid) but it's an important point because it explains why his family is a bunch of power-hungry psychos, and also why his brother is so pissed about him being a teacher. He is literally second in line to a huge financial empire but doesn't give any fucks about it. So yeah.
I choose bachelor #2, please
So why does the Sakaki group care about a private school? After all, they already own tons of them, right? It's because the pharmaceutical data for Suzubishi is stored on the school island (and that's where their research lab is too), and somehow the Sakaki pharma group discovered that Suzubishi is developing the same kind of drug they've been working on for years... only Suzubishi's drug is already in the clinical testing stage and will likely be released soon.
At first, the Sakaki group thought the director of the school had access to the research data, so the plan was to get Professor Sakaki installed as the director to get access. Unfortunately for them, the director does NOT actually have access to the data, and the current director at that time (Endo/Suzubishi Kazuki from GH1) selected his own replacement before the group could make their move anyway. The new director was Suzubishi Nao, Tomo's older brother who was adopted by the Suzubishi family.
Okay, this is getting really complex, so we need to take a couple of detours before continuing the "real" story.
detour #1: Tomo & Nao
Tomo and his older brother Nao were orphaned at a young age. Nao was a sickly child, so trying to get the two brothers adopted together was impossible. Eventually a family adopted Tomo, and later a member of the Suzubishi family adopted Nao. (Tomo and Nao are actually distant relatives of the Suzubishi family.)
Tomo's adoptive family realized that he had potential to become an expert-level hacker, and exploited his talent, using him to steal information from various companies. They were eventually caught and tossed in prison, but Tomo was held harmless since he was a minor. He went back to the orphanage until he was invited to Bell Liberty by Nao. (Totally legit as Tomo had set a national track record in middle school.)
Nao's sickness took a turn for the worse soon after Tomo arrived, and he died shortly afterward - but not before naming Tomo his successor as the school's director. Suzubishi (aka Endo) Kazuki became Tomo's official guardian, but because he's a Busy Dude now, he asked Keita and Dr. Matsuoka to watch over him in his stead. He also asked Professor Sakaki, who was all WTF I am not a babysitter, so I guess that was a no.
Kazuki introduces Tomo to Sakaki
So that's the reason why no one knows who the new director is, not even his name.
detour #2: Sakaki's past
Backing up again to a bit more than two years before the start of the game, when Professor Sakaki was transferred to BL as assistant director. He already had a reputation as a demonic teacher, despite the logic/math of things telling us that he'd only been a teacher for ONE year before getting transferred to BL. Math teachers in Japan are required to have a master's degree, so that's five years of college, making him 23 at graduation. (Typical anime/manga/game super competence and/or time compression, bah.)
Anyway, he'd helped improve the reputation of his school (the one owned by his parents, which was also the high school he himself attended), by being such a ridiculous hardass that dumb students dropped out. Or maybe they transferred away, but the game uses the actual English word "drop out" when describing this so I dunno. This created an environment where only top-level students could make it through, and thus only top-level students would apply, increasing the "quality" of the school.
Okay, ANOTHER little detour here to explain just why Sakaki is such a bitter jerk at the tender age of 25...
better sit down, kids, this is a long tale of woe
In middle school, he was part of a group of three friends (two boys, one girl) who shared an interest in logic puzzles. The other boy was extremely intelligent and from a prominent family (politicians, etc), while the girl was average. The thing is, the genius boy always did very poorly on tests, and since the school only considered grades and not effort, he was nearly failing. The boy's family was very hard on him and assumed that he was goofing off, and eventually the boy sank into despair. His only hope of attending a good high school was to be accepted to Bell Liberty... but that never happened.
However... Sakaki received platinum papers from Bell Liberty. There was no way he would have attended anyway (remember, his family owns a crapload of private schools), so it was like the final insult - his friend was screwed over, but he received entrance papers that he had no intention of using. He got rid of the papers, not wanting his friend (who was smarter and more deserving) to find out.
The super-smart boy eventually dropped out of school, depressed by his poor grades and his family's treatment because of it. It was discovered much later that he had a learning disability (dyslexia, specifically) that affected his ability to perform on written exams. The girl from their circle ended up becoming a teacher, determined to try and create a better learning environment for students with disabilities. She ended up quitting after realizing she wouldn't be able to implement her plans for change.
In short, Sakaki hates Bell Liberty because their student selection method is only based on visible things - grades, contest wins, athletic performance, etc - and doesn't consider an individual's potential. The selected students are all from "enchanted" backgrounds, from good families that already have an advantage in the world. When his family told him to go to BL as assistant director, he grudgingly agreed, partly out of curiosity, but mainly out of a desire for revenge against the place he saw as the source of his friends' suffering.
But when he taught there, it was different from teaching at his family's private school. Instead of giving up, the students of BL grew stronger the more he pushed them. And the students and staff were good people who couldn't be blamed for the school policies. He'd been determined to block Nao's plans to make changes and improve the school, but the two ended up more like friends. (Well, frenemies, anyway.) They spent a lot of time chatting about Nao's idealistic plans, and it seems like Nao's optimism got to Sakaki at least a little bit.
In other words, the school and its people are surprisingly decent.
back to the main story
Okay, back to the Sakaki group being a bunch of douchebags.
Somehow, the Sakaki group has discovered that Tomo was (is) an elite hacker, and they are pressuring him to steal or destroy the Suzubishi drug research that will kill Sakaki pharma if the drug makes it to market first. The plan to close the school has nothing to do with the school itself - it's just the tool the Sakaki group is using to try and force Tomo to comply with their demands.
Basically, they will fuck up the lives of a ton of students for their own gain. Nice, huh?
And at the moment, Professor Sakaki is on board with this plan, because he STILL hates Bell Liberty. On his brother's orders, he has Sonoda steal the armband from Yuki's jacket. Sonoda cooperates because he's been promised a big payoff from the Sakaki group, which he plans to use to buy back the Sonoda brand of food products from Suzubishi. (Spoiler I guess, but by the time you find out what Sakaki's deal is, you've already seen Sonoda's true ending.) Sakaki has no intention of following through on this, but Sonoda doesn't suspect that he's being double crossed, probably because he's known Professor Sakaki for years.
Brief side note: Sonoda's parents are divorced, and his mother remarried about 3 years before the start of the game. Her husband is Professor Sakaki's uncle (his father's younger brother), making Sonoda and the prof step-cousins. They seem to get along pretty well. Then again, there IS the whole double crossing thing, so...
The original plan was for Joker to become student council president, but Joker's aware that Sonoda is up to something fishy (and has been for a long time) and has no intention of cooperating with him. So the armband ends up getting passed over to Professor Sakaki, and that's when he makes the announcement that the school will be closed, Yuki rushes out on stage to argue and gets shot down because he doesn't have the armband, so he has no power to object.
However... the reactions of the students, especially Yuki, start to get to Professor Sakaki. He's already softened up a bit since coming to Bell Liberty - it seems that he used to think it was fine to use students and education for profit, but after teaching there and talking a lot with Nao, he's no longer okay with how his family uses schools. He ends up having a change of heart during the Bell One, not out of any love for the school, but because his own ideals have changed.
The third round of the Bell One is supposed to be a test of luck, where Yuki has to choose which of two boxes contain the armband. In Sonoda's ending, BOTH boxes are empty - Sonoda has rigged the game, intending to force Yuki into either giving up without opening either box, or to fail in front of the entire school, since an image of the boxes is being broadcast to the entire campus. If Yuki decides to believe in his luck and choose a box anyway, a miracle occurs and he recovers the armband that wasn't even in a box!
Except it WAS, because Professor Sakaki put it in one of the boxes when Sonoda wasn't looking.
The school is saved, the students are relieved, and things go back to normal for everyone.
Oh, and remember that grainy security camera video of someone stealing the armband? Professor Sakaki was the one who sent that to Yuki. Yes, even before he saw how everyone reacted to the announcement of the school being closed, he was still pissed off by his family messing around with his place of employment. (Seriously, do not fuck with this man's job.)
The problem is... the Sakaki group may have been thwarted once, but they'll eventually try again. As long as Tomo's the director, they'll keep targeting the school and trying to manipulate him into going after the Suzubishi drug data. At first, Tomo considers hacking into Sakaki and destroying THEIR drug data, but he doesn't really want to get involved in illegal activity again. If he's going to hack, he wants to find some sort of sensitive data that he can use as leverage against the Sakaki group, some sort of proof that they've been mixed up in illegal stuff themselves. But there's no guarantee that he'll be able to find anything before his hacking attempt is noticed.
Again, Professor Sakaki steps in to help - seems like his brother's been cooking the books, and he knows where to find the data that will prove it. With Yuki's help, Tomo assembles a slideshow of images from Bell Liberty, kind of like a promotional video. He hacks their system, displaying the slideshow on all the computers on the network as a distraction while he goes in to steal the incriminating financial data.
director Kasahara has had enough of your bullshit
With that information in hand, Bell Liberty is finally safe.
But you should totally read Sakaki's character route for more details. :3