This anime can easily be described by saying that it is mediocre and generic and it has no reason to be as popular and praised as it is. The reason why I believe this is the case is because of the kind of interesting premise of the show which makes people think that this story and characters are actually mature, complex, or even philosophical (which it isn't, only at a surface level), the waifu bait mc, the episodic Slice of Life (SoL) elements and the presence of the well loved fantasy genre which is so popular these days in the anime community, giving huge generic isekai/fantasy anime vibes (especially the world and characters). While I have no problem with people that simply enjoy something for what it is, going from that to giving this anime only 9's and 10's and calling it anything close to "deep" or "philosophical" is an insult to any piece of writing that actually are this things. If you want something philosophical or deep, I can easily recommend anime such as Kino no Tabi (old version), Serial Experiments Lane and Casshern Sins.
World Building/Power system
Almost non-existent, the author makes things up as he goes along the way. No one explains the different classes which apparently exist, the races and the relationships between them, since there are quite a few of them (apparently they are all friendly with each other, except the demons, who are supposed to be the bad guys cuz that's what all the generic fantasy anime/manga/ln's also do) and kind of explain (on a surface level of course) the presence of magic. You have no history or sense of the world and how every species lives the way they do and no well-established fighting system, which makes this world seem extremely uncooked and was just an afterthought for the author cuz he knew all too well that classic fantasy worlds easily sell and everyone understands them, so he had no reason to think about it. While the demons are made up to be a threat, although to a lower extent, they barely appeared and got mentioned throughout the anime, they were probably put in just to have an occasional fighting sequence and to build anticipation of living threats (which they aren't, cuz Frieren's power is completely broken, so there is no tension or urgency for the party).
To add to the power system argument, the fact that Frieren's main hobby is collecting spells makes the anime even worse, since we are led to believe there are spells for pretty much everything since she collects a huge amount of books regularly on her journies, even before the story starts. Too add to that, how she has so many spells and the most important and even basic ones for battles or problematic situations for some reason don't exist or she doesn't have them is beyond me, especially since she has all kinds of spells for daily chores and needs, but not spells such as one that makes you lack the need for sleep, keep you warm in the cold or makes you see what is an illusion and what is real. But of course, we need some fake tension or to show some struggle with the characters because the existence of magic is used as the author sees fit and whenever it leads to the outcome that the author wishes for and it can easily be excused by saying that "she has so many spells, we don't know which she has or which she doesn't" or "she has so many spells, she can't remember all of them".
Story
The protagonist goes on the journey to the demon king castle to relieve the moments she had with her old party members. This is the kind of show where you should simply enjoy the journey, characters and the SoL elements without putting much thought into it. Too bad that, while I will talk later about why the characters are bad, pretty much every episode Frieren and her gang go to different towns, helping people for a few days, then moving on to another town doing fetch quests and sometimes beating an average bad guy (monsters). Fans of these show will likely tell you that all these moments are to build the characters and their relationships and while that may be true to some extent between 2 of them, Frieren not only doesn't do that, but she doesn't even try to learn more about the humans about which she wants oh so much to learn about, this being one of the main reasons (beside reminiscing about the old party) for why she goes on this journey. You would think that when someone wants to learn about other people or races, they would actually spend a significant amount of time with and questioning them at every chance they get. Not Frieren though, she has never even tried to question humans about their short life spans (compared to hers), how they see themselves compared to other species, or the value of their lives, to name just a few potential questions. Instead, she spends a few days in a town, does some chores for a few townsmen and moves on, constantly thinking about the old party she had which she didn't even try to get to know better even after she had realised that she wants to learn more about them.
Art style
As generic as it can get, you have the average fantasy world with pretty, vibrant colors, cute and moe female character design, and soy boyish male characters (not all but quite many of them, as it is the current trend).
Sound
While I usually don't notice the music and sound effects in anime's, there a few exception when I do so, but not in this anime, the OST is your typical medieval fantasy soundtrack.
Characters
Pretty much all of them can be defined by a simple character trait or stereotype, such as kuudere, another kuudere (the mc and the purple haired girl), the energetic crybaby that gets serious when it counts, for the main party, and drunk priest (get it?it's funny cuz that's a contradiction), serious dwarf and energetic crybaby (again), for the old party of Frieren. They all are the typical good guys with not much else going for them. In fact, for some reason, every single person that they meet on their journey just so happens to be good, except the demons, which are bad, as we all know. the old cast and the frequent flashbacks are used to make you feel bad about Frieren (a bit of emotional manipulation since you don't know any of them in the first few episodes when they appear the most so it's better and easier to make Frieren cry after them instead of building up for at least a few episodes the characters and that crying scene), and to make Frieren realise that she actually knew plenty of things about them and actually had a connection to them. This is considered an important plot point in the story because the anime tries to hammer almost every episode (if not every ep) how much she is starting to remember and care about them, but the story keeps going with the flashbacks even though both the watcher and Frieren understand this after just a few episodes and it still doesn't matter cuz Frieren doesn't change in the least after the first few episodes since she has this revelation and starts her new journey to know more about humans (which she doesn't even try to do, as i pointed out earlier). The least I can give it is that the old party isn't, at least, simply forgotten but a reminder for why Frieren goes on her journey, even though this can be simply canceled due to what I just mentioned.
Focusing on Frieren, the main protagonist, shows just how flawed the execution of its supposed themes in this show is. The fact that she is +1000 years old is one of the selling points and main reasons why this anime is usually praised, since it's something "new" and "original" (and as we all know, new and original=quality, doesn't matter how bad the execution is), but too bad that the aforementioned execution shows that it doesn't even matter if she is +1000 years or 20 years old since you can explore the same themes that this show pretends to explore in the exact same way and you wouldn't feel a difference. Actually, it would be even better like this, since she acts like a 5 year old that constantly needs to be spoon fed, woken up and dressed by her kuudere companion, despite her age. She was also a social outcast for hundreds of years , but good thing she ain't a +20 year old shut-in male who collects figurines and posters and suddenly tries to become more social, but a +1000 years cute woman elf that collects spells and only knows how to live like this, despite the years of experience, self reflection and time that she had to change over this period of time, because it would be quite clear who would be more appreciated and liked by the watchers. It is literally impossible to suspend your disbelief that she can still act like a child and have no maturity whatsoever after all this time if you have basic human knowledge and know that change can happen, even just by getting older (not to mention the life experience that she more or less has, even by simply existing) (and since there is no explanation, as far as I know, about the difference in development of human and elves, it's easier to go by human logic since they are extremely similar, except their pointy ears and long life span, which doesn't excuse the almost non-existent development from her childlike state). Neither her behavior, nor her thoughts show anything that could make me point to her and say she is actually a deep or complex characters used to explore themes such as the importance of bonds, of life, the inevitability of death, and the fact that the author just slaps over all her childish elements "+1000" years doesn't change anything about her shallowness, she is just a moe waifu bait who is liked only because she is a cute female, seing a +1000 year old male acting and being treated by others like she is creating quite the different perception of how a person should be at that age.
While I have nothing to say about the rest of the cast except that they are generic characters that are easily replaceable (which would be preferable since it would create more interesting dynamics than the ones in here), I at least enjoyed some of the interactions between purple hair girl and red hair boy, despite the fact that they don't add anything to the anime, not in term of themes, nor of story, especially the purple haired, since this anime shows you just how bland a cast of characters can be if you have more than 1 kuudere, red hair boy being used to liven the atmosphere a little (though it doesn't change much since the show is still boring and bland and mediocre due to the many reasons I presented here).
Conclusion
So yea, this show has nothing going for it except it's empty premise which the anime fails to build upon or execute even in a relatively competent way, being one of the most generic anime i have the (dis)pleasure to watch, but I am quite curious to see if it will even try to do anything better than it currently does, or it will remain an empty premise which the author isn't capable in the least to do something with.
