Religion is a strange thing to study in most, if not all, nations. Especially when those ideas began elsewhere. And if you’ve been watching anime for quite some time, you’ll likely have noticed that western ideas tend to get a bit… warped on the other side of the Pacific.
As seen in shows like The Devil is a Part-Timer, what is usually thought of as “Christian” in terms of theology and Biblical stories doesn’t come out clear in most anime. Often it’s a combination of Catholic, mythic tales, and various elements of other religions, namely the national religion of Japan: Shinto.
Now some might ask why I make the distinction of Catholic and “mythical” stories, implying they are not “Christian.” However, I note this because 1) many Catholic traditions and mythical stories are not found in the Bible, but pushed off as if they were. 2) Both these elements were brought to Japan before the more Evangelical Christian beliefs were. By the time Evangelical Christian missionaries arrived, Catholicism had already built itself a niche, mainly due to it being flexible enough to accept aspects of the Shinto religion, blending the concepts together.
Any amount of basic research into Catholicism will likely clue you in as to why anime seems to have very strange ideas about western religions. From an outside point of view, there is the worship of many individuals who are treated as gods rather than mere man, angels whose names should be memorized, sin and the devil are often given a great deal of attention (most commonly in cautionary tales told to children) and then God Himself, who is often treated as a far distant Creator disconnected with His work. While some within the religion would likely claim otherwise, remember that this surface impression was what Japan (and really anyone from the outside) saw and often continue to see. And with high tensions between the Japanese and foreigners running deep by the time missionaries began to appear, very few even attempted to right these strange assumptions, nor did they try to keep their religion from blending with Shinto, which only made the misunderstandings deeper.
Of course, as is forever true with media, overblown rumors, misconceptions and stereotypes are rampant. What one sees in media should always be taken with a spoonful (if not a bowlful) of salt. Unless one doesn’t like salt. Then perhaps sugar.
Anyway, it does stand to reason, however, that if these strange trends are seen too often, there is likely good cause for their presence.
(Days later I find that I clicked the Save Draft instead of the Publish button. Keepin’ it classy. Sorry folks. One day I’ll learn to not trust my senses at 3am. One day.)