When Oberon suggested retreating, Shen Fei did not step forward and volunteer to deal with King Mores. He would wait until Castoria made her decision before deciding whether to act. This was, after all, a matter for the Fae Country. They had already done plenty by coming this far. Even retreating now would have been a normal response.
Neither he nor Chaldea was some saintly savior. Mash and Ritsuka were kind-hearted, but everything they had experienced along the way—especially their journey through the Lostbelts after Humanity Freezing—had taught them that there was no way to have it both ways. To save Pan-Human History, they had to cut down the Imaginary Trees and destroy the Lostbelts.
In the original work, the moment Mash saw King Mores appear, she charged forward without a second thought. Oberon had even lamented that no one stopped her. This time, however, Mash was not so impulsive. Without her experiences in Sheffield after losing her memories in the Nameless Forest, she was still kind, but not to the extent of disregarding her own life for Norwich.
Many of Mash's actions in the Fae Country Lostbelt in the original work had seemed as though she had lost her mind. She had not even objected to marrying Boggart. That was not merely amnesia—it was a complete loss of common sense. Losing one's memories did not mean losing one's common sense. Ritsuka's behavior in the Nameless Forest, and Tristan's as well, made that clear enough.
The reason Mash had acted that way was related to her birth. As a Homunculus, she had begun as a complete blank slate. Her amnesia had returned her to that initial state, leaving her unable to refuse anything. Even when she was sold, she believed those three Goblin merchants were good people. No ordinary person,