Oh, magic advancing! You don't see that in most fantasy stories, the oldest magic is usually the most powerful. Usually cause they're, consciously or not, inspired by Tolkien where the older ages were ones of magic while as time advances it goes away. No wonder Frieren still finds magic interesting, even as an elf. It's changing at breakneck speed as far as she's concerned.
This is something special. I hope it's popular in Japan.