The first and foremost aspect that needs to be said is to forget about doubts you might foster regarding the crossing over of several subgenres, where this set could easily fill the shoes of pioneering ways to blend an unexpected compilation of reading classifications; coming of age, mythology, young adult, speculative fiction (fantasy), epic and contemporary fantasies, action and adventure, mythology and historical roots, to name but several without having to search for ideas.
Katana is the kind of destiny rich character who grows and hooks you greater as the books progress. Her mentor, best friends, teachers and even her nemeses become as important as she within the first book; leading to a growing fascination with all. She has a fated past that shapes who destiny, and your awareness of this and the importance it bestows takes it from sadness to relevance. From the onset of her teens, and thus the storyline, her winning personality not only opens doors for the way she makes new friends, and keeps them, makes the story all the more endearing and hard to put down. The challenges she faces are endowed in mythology, or perhaps historical drama could be the better way to describe them. The first book falls into my top five first in series stories that pave a way to outstanding series. Furthermore, top five boxsets, top five for arousing an unstoppable need to read-on, top five blending of multidisciplinary genres, top five for all books in a series being as outstanding as one another... and top five ___ so on and so forth.
If you're a fantasy fanatic who seeks out being dazzled in unexpected ways, then The Katana Series is without compare. If you love fantasy and want blends that tantalise in unexpected and enduring ways, reinventing your ideas and love of them in ground breaking new ways then this series is for you. If you're a martial art/action aficionado who seeks historical telling with traces of mythology in its dawning years then this is for you. If you want to tantalised in new ways you couldn't predict if you tried then this is the series for you.
In essence it should be obvious that I have no negative impressions of these stories, only wonderful positive impressions, and that the blending permits the series to air in new ways without compare. The environments, characters, content, completeness of the final story, and a myriad of other reasons are present for your delights. At its present steal of a price tag you'd be a mug if you failed to take up this incomparable opportunity to get these benefits for less than an individually costed price of near to $AU0.30 (even when rounded up) for each entry makes it one of the greatest steals you'll have gotten for 2020.
In a tally sporting more than several hundred books from the typical sub-genres of fantasy reading, I struggle to recall comparable examples (or even a single example whatsoever). For me it's up there with The Shannara Series for impact on my fantasy preferences. Indeed, straight off the bat I'd say they're an equal first in my top fives, The Shannara collection perhaps only winning out because of its sheer size. But such a comparison is exemplary in the dangers of using such a dimension to decide what stories you want to read. I can't even constructively feed back any info for Ken to take onboard, or for your consideration, as all the aforementioned shows how the positives come to light.
Purchase it, read it, review it/them: as I have every confidence these choices will see you arriving at the same pleasurable outcome, and I dare you to read the series and thus find out for yourself if my review is incorrect... because I haven't and you won't. Furthermore, this is all from the perspective of an early forties reader, so if I didn't find the ages restrictive in any manner, then neither should you: so don't let premature ideas about age relevance lead you astray.