This feels like a staple story just here the boy is way to overpowered to make sense. How did they even annhilate all of them, if even a small boy can completely decimate robo armys effortlessly per "plotdevice".
Tho he also wrote Claymore and that 1 was riddled with holes in the later half, but at least he didnt rush that story like here. A story isnt fun to read if theres no stakes. Would be like making Teresa the protagonist of Claymore and saying fuck the stakes and suspension just let her oneshot everything and travel the world with raki.