*Spoilers be warned, this review will have some context that's relevant to the overall story*
What comes to your mind when you hear of the word "Isekai"? As a genre made famous from the tropes it originated from, the popularity that literally started its rise and downfall with SAO, and the momentum of shows like it has never stopped. Giving us the great likeness of Re:Zero to the horrendous worsts like Isekai Smartphone, there exists an Isekai for everyone, but not all of them are masterpieces of their own right. Seirei Gensouki on the other hand, touts to be just that and more: a carbon copy of SAO, but there is a major key difference that sets it apart.
Let's get the similarities out of the way for most of the anime-onlies being simpletons for comparison: Haruto Amakawa a.k.a Rio (in the fantasy world) is pretty much a less-refined version of Kirito, from the behaviour (which looks more lax than said character) to even the costume which looks eerily similar the the Black Swordsman coat. Rio no doubt has a harem of girls kissing up his ass, but just hold that thought for later on. Most of the baddie villains are similarly one-toned evil with boisterously filled egos that are meant for the MC to trump justice with good against evil, but most of the time he does nothing against it. Which begs the Gary Stu of a character of questioning why wouldn't he be rescuing those in danger, but like the others before it, there's a very specific reason behind all of this ordeal.
If you can get past all the blatant similarities of how Seirei Gensouki is just another work of literate copy-and-paste Isekai tropes, then this is where the proof of the redemption story of novelist Yuri Kitayama's writing capabilities lies at: it's not just your typical, generic Isekai story plot, but something that will have you going back and forth of reading between the lines of what was presented and piecing those plots together in the span of different timelines. I would like to give a shoutout to Typecero, because this guy is a devout fan of Seirei Gensouki, and most of the analyses done was in no small part his work, and this review is made possible because of his episodic breakdowns which made the big picture clearer between the anime adaptation and its changes when compared to the source material.
So, in the beginning, characters do get brutally Isekai-ed in a wayward bus onto an incoming train, but the thing is that the characters in the bus are not one-trick ponies who are just Isekai-ed into the fantasy world. See, for the main character Rio, he isn't just some generic Isekai character, but one that's of reincarnation and fused with the original person's (Haruto Amakawa) memories. An orphan living in the slums of the new world, and wanting to find revenge on the person whom killed his mother at a young age. To make things more complicated, the kidnapping of princesses gets him unequivocally involved (which he saved), which lands him in the walls of royalty for a commoner such as Rio to attend school, only to get ridiculed by the usual hierarchy social status of commoner and arrogant nobles, children or adult, they're all the same. Being falsely accused of anything and everything of noble status, Rio is labelled as a fugutive to the point of literally being forced to escape from the Bertram kingdom, which continues smearing his name left and right.
It's not just Rio who suffers this kind of usual historic barbarism of instigating the superiority of nobles. Take the young fox girl Latifa for example. Like Rio, she was subjected to slavery, and being a tool for the royal family as their controlled assassin to hunt Rio down to kill him when he was forced to flee from the kingdom. Thankfully Rio was able to get her out of her predicament, to which then she followed him on his lone journey, becoming his adoptive sister. If anything (and this might come off as a spoiler) that you should pay attention about, Latifa is one of the passengers on the bus with Rio (the real world Haruto), and she is known as Endo Suzune, another charcter reincarnation into the new world. See, I told you that characters in Seirei Gensouki aren't just walking tropes.
The thing that's so interesting (but sadly generic for a "prologue" of sorts) about Seirei Gensouki is the world-building that's between characters, the factions within kingdoms and not to mention, Rio's "harem" of girls that admire him for what he does like Maou Gakuin's Anos Voldigoad. Most of the content would already be going into spoilers since the anime's plot had one major development skipped that made or broke the overall tone of the series, but I can share a few details while keeping vague. Let's take Rio's teacher, silver loli Celia Claire for example: she was the one whom took care of Rio when he was being taught at Betram Royal Academy, overseeing his progress to the point of gradually being in love with him. Yes, you saw that right, a teacher-student relationship that built up to a point where the anime resurfaced back again with the passing of timelines to make it relevant. Another significant character is the pink-haired Aishia, whom is Rio's spirit of a contractual awakening of a "special power", and for better or worse, this is where novel fans went all gaga about her. Because from the time she appeared in the original source material, everything appears to have a drastic change of course within the timeline of its spectrums, and for good reason to shift the tonal direction of the novel. Even villains (or rather antagonists) like noble Charles Arbor accumulated all karma from oppressing Rio at the initial stages of the anime, get their break from being served that under their noses. You see, the various intertwinings of the factions and the characters belonging to the faction they come from, carries the weight of the name they bore, So for Rio to sense any injustice and fight back, he literally cannot do so as it would be treason on the part of the family and people held responsible, not Rio. The dreaded "harem" is something that I'd left must be concerned, because it's through the actions that Rio does to infatuate the girls' hearts, not by sheer looks alone. Rio is admired because he is a hero to them, and ladies fawn to heroes because of this.
On that note, I'd highly recommend you to read the manga or light novel if you're interested, because while I cannot cover that much hidden context of what the anime presented, the world of Seirei Gensouki is much larger than life when compared to the anime adaptation. Because while it isn't bad, the tropes that we've seen time and time again are the result of compressing such a big story as this from the hands of the production team. Led by veteran director Osamu Yamasaki in both direction, script and series composition, they tried their best to stack as much content, while making some questionable narrative decisions that relegated Seirei Gensouki to the average Isekai lookalike of a show that even novel fans have to concede that it's labelled as such. What a disappointment.
Other than that, I'd feel that this is a show where without the knowledge impartation from novel fans, anime-onlies will not feel lost, but just feeling that average, mediocrity of subpar-ness of tropes seen one too many times before, compiled in one complete package that is this show. If you're like me, seek out the forum discussion topic that I created explaining all about the adaptation comparison so that everyone can be on the same page. Bear in mind that it's full-on spoilers, so watch the anime before reading the hefty few-thousand word episodic essays. At first, I was gonna shrug this show off as just the typical "not bad, but not good either" Isekai show, but thanks to people like Typecero, I get to understand this show better a lot and have some appreciation for Yuri Kitayama for a generic story that can go as deep as it could to prove the naysayers wrong. The novel truly has its hardcore fans for reasons such as this.
Animation-wise, Seirei Gensouki just exists. Given that this is TMS Entertainment with WAO World for co-production, it just looks fine and nice while smelling that limited budget work. Not spectacular, but as I've mentioned time and time again, it's serviceable on all fronts. While I feel jaded that the OST didn't really come off as something unique, there is at least some creativity in the OP/ED visuals which are foreshadowing the story. For one, there are 2 versions of the OP: one that you normally see on Crunchyroll, and there's the Bilibili version which has the same narrative tone, albeit with a few differences that novel fans (and eagle-eyed anime-onlies) will recognize very subliminally. Are you surprised to hear of this? I bet you were if you're paying attention. The songs and the artistes helming them also sound very generic, but Aguri Oonishi's "Elder flower" for the ED is one hell of a good song. But just like the rest of the show, you've guessed it: it's average across the board.
Back to the main point, Seirei Gensouki a.k.a Spirit Chroncles won't ever break the bank out of the hellhole that is the Isekai genre. And since it originated from the Isekai lands of Syosetu (which is where you'll see works like Mushoku Tensei, TenSura etc.), be prepared for some of the most average Isekai tried-and-true formulas just repeatedly conspiring together for a story well short of initial expectations. I also highly doubt that anime-onlies like myself will ever want to read the original source material since the adaptation has some minor missteps that gave it a major disservice. All in all, it's the same average and repetitive "You can pass this show up for better shows" cliche rhetoric or metaphor, and my hope has already diminished since Day One when this anime started to tingle my bored antennas, that slowly but surely spearheaded into pure disconnect.