Japan has a rather fuzzy view of Christianity (sort of to how the West generally has little clue about Shinto), but they like the aesthetic THEMES of it. So you often see non-denominational but vaguely Christian-like Priests in Japanese games, in Gothic looking cathedrals, but the religion itself is very vaguely developed or downright inaccurate in a few aspects (I remember Ghost Hunt has a 19-year old Catholic exorcist, when you can't even be ordained at 19).

In short, religion in (Fantasy) games is usually not meant to reflect any real world religion besides the superficial.