>>45913482Christianity has a lengthy history in Japan and even today about 3 million residents of Japan are Christian. That doesn’t even go into shit like 70% of weddings being Christian or the fact that eight Prime Ministers have been Christian as well as all of the Christian symbology and themes in Japanese games, many final bosses being based off the biblical God. It’s plausible to argue the origins of Arceus are rather broad but Giratina is pretty clearly based on the concept of fallen angels, particularly Lucifer who is a VERay popular figure in Japanese fiction, like Lucemon or how every other light novel features a Luciferian character.
Point being, Christianity is pretty influential in Japan and is a frequent source of inspiration for game makers and writers.