The anime (23 episodes, 2021-22) is fantastic, but it wasn't actually adapted from this. The original source material is a military SF light novel series that's actually still running. So far, it has 14 volumes and two side stories. This is a manga adaptation that went on hiatus due to the artist's health issues before being cancelled after only three volumes. There have since been comedic or alt-universe spin-off manga, though: 86: Operation High School, 86: Run Through the Battlefront, 86: Fragmental Neoteny and 86: Mahou Shoujo Regina Lena - Tatakae! Ginga Koukou Senkan San Magnolia.

This is the first of the main manga's three volumes. It's a war story. The Republic of San Magnolia is fighting the autonomous drone army of the Giadian Empire. The Republic claims its weapons are unmanned with zero casualties, but this is only correct if you accept their relegation of an ethnic minority to "non-human" status. People called the "Eighty-Six" are forced to pilot these mechs on the battlefield, dying like flies as they're guided by remote control by "handlers" from the Republic.

This manga volume isn't that great, despite a fantastic start. The best thing about it is the art. Motoki Yoshihara's superb at drawing those mechanical spider-mechs. He draws lines so precise that you might wonder if he's a trained mechanical engineer. You could give these pages as blueprints to an machine building team and they'd hardly need anything more to start work. Yoshihara's war machines feel real. Then, though, we visit the beautifully peaceful city of the Republic and you might wonder if Yoshihara was also once a professional building surveyor (like Dave Gibbons). These pages are gorgeous... until we reach the silly big-eyed anime girls who don't fit the rest of the artist's style. On their own, they're fine. They're stereotypical manga faces. We've seen millions of them elsewhere. However, they're jarring in the same book as that photorealistically accurate character design on some random bloke we'd met only a few pages earlier.

Oooh, just noticed something. The manga also has a cover credit for "mechanical design" (to someone who goes under the name of "I-IV").

The script might also trip you up. At first, it's shocking. Comparing the 86 warzone and the smug, racist handlers will make you want the enemy to win and exterminate them. (However, there's also a nice handler who cares about her charges and doesn't laugh it off as nothing when they die. Her colleagues sneer at her.) After a while, though, the manga flips a switch. Right, that's the gore and horror out of the way, let's introduce the cute lovable cast (although in the next book we'll probably start killing them too). That's where we get the visual clash with those cute big-eyed manga girls, although I liked the skeleton under a tree.

The pacing is very manga, i.e. slow. It takes lots of pages to make relatively little story progress. That's normal for manga, admittedly, but problematic when a series gets cancelled (like this). I wouldn't particularly recommend this volume... yet, paradoxically, it's very impressive. The art is beautiful and even those clashing character designs are in themselves perfectly well drawn. Meanwhile, the story's concepts will burn themselves into your brain and you'll hate those Republic bastards like poison. It's powerful stuff... but you'd be better off with the anime (or possibly the light novels, although I can't vouch for those personally).