EDIT: Downvoted for asking questions?
I'm opening a can of worms, I know, but I imagine that in terms of religious faith, Demacia wouldn't have followers of Nagakabouros. They might even consider such a deity a "blasphemous" concept.
So... is there any sort of religion used in Demacia? Or is that sensitive information that Riot won't release until later?
Personally, I hope it wouldn't be TOO similar, although that depends on what kind of Christianity we are talking about.
Christianity is becoming increasingly decentralized, so it's hard to make generalizations like that.
Ever played D&D? I imagine their "religion" as being followers of Bahamut. You can look up what that entails elsewhere, but it basically involves justice and protecting the weak.
Christianity also has some of that, but in particular, the God of Christianity is portrayed as merciful. I don't see Demacians as being particularly merciful. They believe in swift, absolute justice.
Christianity...eh...I would assume it'd be a form of Catholicism which was more of a widespread thing 17th and 18th century Spain, England, and France.
They DO have religions, how many? I dont know, but Aatrox is seen as a "God" or something like that for some Demacians (Aatrox Justicar)
And they also believe in 
Kindred... however, i doubt that they have a "GarenJesus" that spinned for their sins or something similar.
I see Demacia having a pantheon of gods rather than a singular religion. They probably have a host of gods. Some with obscure followings. Others probably more popular thoughout their culture.
GTFO
Well one Demacian religious figure is the Veiled Lady, who seems to be linked to the afterlife specifically, which I personally take as a more somber perspective of life after death, as it's hidden behind a veil. I'd imagine Demacian religion is more like the doctrine presented in the crusades more than modern christianity, and by that extention, their religion is probably way more about actively bringing about what they believe to be good in the world.
Christianity, if we're going on the core tenets, isn't a terribly great fit for a people who focus primarily on station and duty (with a healthy helping of corporate good).
I would argue that basing their religion loosely on Hinduism would be a much better fit.
Personally I don't think there's room for religion in Demacia, unless you consider their complete and total adoration of their king and views to be a religion. A lot of parallels can be made toward real life organized religion, but I don't think there's anything more. They are an absolute monarchy and religious beliefs could cause a citizen to side with their beliefs instead of their leadership under rare circumstances.
This is, of course, taking our current knowledge of Demacia into account. Until Fiora's new lore came out there was no evidence of Demacia being patriarchal, so who knows. All I know is if there is a religion in the RL sense it is state approved, and there is only one allowed.
I wouldn't be surprised if there was some sort of "divine right" justification for the Jarvan line. Some sort of religious background would probably help reinforce the monarchy that seems to be the backbone of their social system.
