How did the title of "Devil" come from during the War of Resistance against Japanese Aggression period?

The word "foreign devil" comes from western invaders (it is easy to explain: "Japanese soldiers invaded the land on the other side"). After the Sino-Japanese War of 1894-1895, "devil" was also used to refer to the Japanese aggressors.

After the end of War of Resistance against Japanese Aggression, "Japanese devil" evolved into a general disparaging term for Japanese in China. "Japanese devils" are sometimes referred to as "devils" for short. For example, the "devil" in the movie "Here comes the devil" and the "devil" in the song "Here comes the devil" refer to the Japanese aggressors.

Some Japanese critics have pointed out that due to the different cultures of the two places, Japanese culture regards ghosts as a symbol of great power, but it is not necessarily as inhuman as China culture, so even if you see a demonstration slogan with Japanese devils written on it in China, it is difficult to understand the derogatory meaning of this derogatory term.