So I'm a Spider, So What? Novel Volume 12 was written by Okina Baba and illustrated by Tsukasa Kiryu.

Whoa, war's broken out and it looks like it'll be this world's deadliest. Yeesh. The Demon Lord is doing her best and it looks like the only one who might be able to stand in her way is some hero named Julius. If I'm going to help the Demon Lord figure out this world peace thing, then he's gotta go down!