SouSou no Frieren is a story about an elf and her life after slaying the demon lord in the hero’s party. More importantly, it's a story about age and immortality.

Something usually glossed over in typical fantasy when mentioned that an elf is over a 1000 y/o old besides a justification of something gross.

In casual passing it’s mentioned how the character and her human apprentice will stay 6 months or even 3 years doing something trivial or just waiting around.
In any other scenario this would be a shock considering how long a time that is, but for an elf it's hardly a minute. This comes off a well written meta narration to give perspective to how the main character sees time and the world around her.

How a character who has gone emotionally numb knowing that nothing around her matters if it's gone before she can blink and watching people she's slowly learned to care about slow age and wither before her is a big focus in the story and a very touching one at that.

Emphasis on “slowly learning to care about” as she only realizes that she cares about them by the time they’ve already passed away or are at the last inches of their life.
Why else would an elf that lived for 2000 years care so deeply about 13 years spent adventuring with a group of strangers.

It’s a little funny how heartbreaking it is to think about for any other character around her.
But really makes you root for her to try and find meaning and open up.
A thought captured in hardly any of today’s literature let alone manga.

When you die you want the people around you to remember you and remember all the accomplishments you’ve made.
That's something easy for humans or dwarfs to do, but for elves it's impossible as after the several millennia they've been alive, everything they've built up, every feat they’ve done to shape the world, the great evils they’ve defeated, is lost to history as no one is alive to remember them through it all.

Watching an elf learn what it means to care about others in the face of this void that casts absolute pessimism and in turn realize how much the people she's befriended meant to her is an emotional rollercoaster and executed in an excellent and perfect manner both in story and meta narration.

This thoughtful story telling carries on to the world the main character inhabits and how things like demons, monsters, mana, power, and magic, operate, function, and interact with each other.
While not going off on tangents that take away from the main focus and message.

Kind like what I’m about to do now:
I also like how it uses the german language for it's fictional names and characters rather than japanese ones.
I’ll be it simple words or phrases.
It's a nice return to traditional fantasy.

Makes me feel like the writer is a big fan of these more traditional works or just likes DnD a lot.

Anyway:
SouSou no Frieren is an easy 10/10 and a highly recommended read for anyone who has a feeling of wanting a break from the typical shonen, romance, or comedy genres to explore a well thought out and meaningful story.

Btw are you tired of me saying thoughtful yet?