What do you see behind your window? [Link to plenty of GAs]

You're welcome :) I hope you can convince them! :D

The Last Question is a great story.

So, there are a lot of groups of Christians, and the terminology to describe them is quite vague. One simple way to divide it is major tradition- Protestant, Catholic, and Orthodox are how I would identify the traditions. Catholic and Orthodox tend to be more monolithic- they follow one hierarchical structure and it's relatively simple, though Orthodox churches tend to separate by cultural groups, languages, or nations (i.e. Greek Orthodox, Russian Orthodox, Egyptian Orthodox). The Catholic church has many orders, like the Jesuits or Franciscans, but they all are loyal to the Papacy, to some extent, as the head of the church. Protestant churches, on the other hand, are incredibly diverse, with easily thousands of denominations. These are kind of fluid, and they don't all disagree theologically but they often have divisions on major theological points, although they have a core of orthodoxy (proper belief) that unites their core theological understandings (like the Trinity, the Resurrection, etc.) and gives them some common ground, even if they disagree. Their big beef is with Catholicism and the idea of one human being the head of the theological institutions of the church, though they have become friendlier to Catholicism (and vice-versa) after Vatican II (a Catholic council) softened the Catholic church's stance on Protestants and Orthodox Christians- previously they were heretics going to Hell, no questions asked, but now if you hold proper Christian faith you can be saved (at least in theory, under some circumstances). The Protestant community is made up of denominations (what I thought of when you said sections). These have specific reasons for formation, but often it has to do with a reaction to a communal need or theological crisis- Lutherans broke from the Catholic church over the issues of indulgences, or buying salvation from sins using wealth, among other things, while denominations like the Salvation Army (which is actually a church, not just a charity) and the Church of the Nazarene (to which I belong) formed in response to problems in the community like alcoholism, poverty, and domestic abuse. There are significant differences among Protestant denominations, ranging from trivial (structure of a worship service, or what we call pastors/priests/preachers) to the more significant (who will be saved, how people are saved, can women be ministers?). However, most Protestants recognize most other Protestants to be Christians, even if not always good ones. An example of theological creeds for Protestants, if a little specific and refined, can be found in the Articles of Faith of a denomination (though the term for these varies) such as the one found in the Nazarene manual (yes, we make a manual. We're nerds. If you don't want to read it in English, there are also tons of translations here). Of course, in the Church there is often the issue of Christians who are not theologically Christian, that is, people who go to a church and do Christian things but aren't truly Christian in belief or behavior, but that's an issue for another time.

To make it more complicated, there are pseudo-Christian sects, like Mormonism, Seventh Day Adventists, and J------h's Witnesses (I don't use tetragrammatisms, or names for God derived from the Hebrew name for God, so I can't actually accurately name them. but the link should let you know if you're curious) that differ from the agreed core beliefs of the Christian Church (Church referring to the complete Christian community, as opposed to church which refers to a smaller group) by one way or another so severely that they no longer resemble normative Christians. Unitarians also do this (denying the Trinity) and there are way more sects that have similar non-Christian beliefs- even some that seem to be normal Christian denominations. These are usually recognized as such though, even if they do claim to be Christian, but the larger category of Protestants (Catholics and Orthodox churches, on the other hand, are skeptical even of Protestants, so it goes without saying that they agree with Protestants here) denies that these sects are truly Christian. The Articles of Faith that are listed in the manual, though a more exclusive view of Christianity, are similar to those used as a metric to determine if a sect is "Christian" or not- while something like article X (sanctification) is pretty much a Nazarene thing, others (I, Trinity, II, Christ, III, Holy Spirit, IV, Scripture, V, Sin, VI, Atonement to be specific) are considered pretty essential to Christian faith, though the exact expression of these tenets may vary.

As to your question about artifacts... Well, there's a lot there.
So, Catholic mysticism is pretty significant in the historical Church, and many things like relics and artifacts found in fiction have their basis in real relics, which are items or remains of saints venerated because of the holiness of that individual. The Catholic church names saints (Protestants are kinda sketched out by this practice, but recognize that some people are exceptional Christians) based on a number of criteria, including documented or widely observed miracles performed by or happening by the presence of a saint. Whether these are real or fabricated (an issue for another time), relics are often thought to have a potential to serve as sort of a prayer focus, that is, to intercede for the person praying as if the saint were praying (I'm explaining this poorly as my knowledge of Catholic doctrine is bad, but essentially Catholics believe dead saints can pray and intercede for other Christians who are alive, and their purity makes them better advocates. Protestants don't believe in that sort of intercession, for the most part, and believe that all Christians are equal before God, so praying with a saint interceding is nonsense to most Protestants) and this makes their prayers more powerful, and perhaps even that certain relics have miraculous properties. To answer your particular example about the tablets... ugh, this is hard, because I don't know the reference, but I'd guess it's probably referencing Enochian and perhaps a bit of Kabbalah (a form of Jewish mysticism) though I don't know for sure. For the most part, relics aren't really a concern for modern Protestants, though there are superstitious beliefs that certain artifacts, like a piece of the True Cross, (the cross on which Christ was crucified) would have healing powers, but such stuff is considered to be superstition at worst and miraculous, though nothing world changing, at best.

Wow, this has gotten really long. I think I at least tried to answer the questions, but I'll try to respond to any I forgot about.

Not sure if they are not posessed already....

View attached image.

Yep, it's a really nice area nowadays. I have a friend who used to live just a few 100 meters from it, and I'm actually looking at what an apartment would cost in that general area. A far cry from what it looked like just 7 years ago (I don't know if that picture is from 7 years ago, or from slightly earlier, but it's from this side of 2000 at least):

View attached image.

Ich schaffe es nichtmals das richtig in Deutsch zu beschreiben, also versuche ich es erst garnicht in Englisch.
Dachschräge, Fenster geöffnet aber Kamera nicht ganz aus dem Fenster rausgehalten, weil ich dann doch ein Schisser war, weil was sollen die Nachbarn denken, sollten die gerade aus dem Fenster schielen. Stoff-Jalousie war unten und deswegen ist das Fenster schwarz.