So I'm a Spider, So What?, Vol. 7 (light novel) - Jenny McKeon, Okina Baba, Tsukasa Kiryu

Seriously! What genre is this?! So get this…Me, the Demon Lord, the baby bloodsucker, Mera, and the puppet posse are on our way to the demon territory when Mera falls into a hole and gets attacked by giant ants. We wipe ’em out in no time, but the commotion (and totally not me sticking my nose where it doesn’t belong) just haaappens to wake up some ancient, hyper-advanced killing machines, and now the entire planet is gonna be destroyed! It’s such a big deal that Güli-güli, the pontiff, and even Potimas are teaming up with the Demon Lord. Wait, when did they all get so chummy? And I’m sorry, what? They want ME to take out the main weapon?! No waaay!