The emotional core of the episode is the revelation of past, which explains his chronic memory loss.
Amid the chaos, Saitou deduces that the spirit’s attacks follow a pattern and suggests a risky counter-measure that leverages Morlock’s time-stopping magic to turn the tide. Morlock’s Tragic Backstory Benriya Saitou-san, Isekai ni Iku Episode 6
Even with multiple adventuring parties working together—including Lilyza , Gible , and the Septicolor Knights —they struggle to defend against the spirit's overwhelming light magic. The emotional core of the episode is the