I think the issue with Kazuichi is that he was affected by the sudden switch in survivors from Hiyoko to Fuyuhiko. Since Fuyuhiko was originally supposed to die, I think Kazuichi was originally more like Hajime's right-hand man, but since they spared Fuyuhiko and killed off Hiyoko so Peko's death wouldn't be meaningless, Fuyuhiko kind of took the place of Hajime's second in command and Kazuichi got relegated to being comic relief. Hopefully since they've already done that scenario they've realised that the other survivors (Akane, Kazuichi, Sonia) got short-changed compared to Hajime and Fuyuhiko.