With the addition of Arisu to his travel party, the group trudged by the edge of the forest, absorbing the post-apocalyptic sceneries of destroyed cities that were right by the border from where they walked.
Kazuichi was genuinely curious about the Kazuichi Stronghold, and he couldn't believe just how powerful Arisu made it out to be. He was aware that Arisu wasn't overexaggerating, but based on what she said, he still couldn't process it due to how ridiculous it was.
As for Arisu, she was led to believe that all strongholds were twice as powerful as the Kazuichi Stronghold. No, she was positive that the other strongholds have an army of Hybrids and a gathering of survivors which were so efficient that they basically fuel the entire place.
Since she spent all her time watching over Kazuichi Stronghold, she had no idea how formidable the other strongholds were. Hence she assumed that they were impregnable like an actual fortress.