Got interested in this after I saw an extra page from the end of the volume of the giant ape fella; I wasn't a big Sekiro fan but with my limited knowledge it looked cool.
Simple story following Hanbei, his past and all of that good stuff. Short and simple fights (the artwork's nothing to clamor about most of the time but it serves its purpose well), not exactly a literary masterpiece but the trope characters were cute too.
I liked the ending, felt fitting for that somber FROM SOFTWARE tone of the Sekiro universe, though at the same time a little expected (since you know where he ends up in the game, of course).
Best manga ever: if you're into Sekiro and want to know more about its titular Soulsbro character and some extra lore and visualization on events, give it a read; it is only a pretty quick 8 chapters (though I did stall for a little bit, haha). For others, it'll just depend on how good of a mood you're in for a little fantastical samurai story.