I am new to the community of Dark Souls and I have made many thoughts about the games lore and did some recherche about the lore and the origins of the game.
I wont post everything I found out here because it is too much and it wouldn't be fun to spoil everything for you as the journey for answers is the most fun part of the game and will leave you with fond memories for ages .
The Celtic origins
Many of you know the Arthurian epic story about Picts, Excalibur, Witches and stuff.
So first of all, many of the names of the epos are found also in Dark Souls.
One of this names is the name Gawain, or if you pronounce the vocals short ,,Gwyn".
Gawain was one of the knights of King Arthur. He did some cool stuff but that is not important here.
Important is his family: His father was the god Lugh, and at the times of the old Celtics he was the god of the Sun.
(Well, he was, because over the time the Celtics changed their gods and they were replaced by Christian, Nordic and Germanic gods.)
So, as Lugh ( from Germanic ,,lucht" and German ,,Licht") was Gwains father, Gwains power was none at night but got stronger in the morning, and was strongest at noon, only to fade again.
(My personal interpretation of the Dark Sign is also an Eclipse or the Earth in front of the sun but that is just sepculation. But think about it .)
Another thing is the old celtic word ,,lond" . It means ,,wild" and is speculated to be the origin of the city London.
Well, also in Dark Souls we have the word lond, twice.
Anor Londo: lond= wild but Anor = ?
I googled ,,Anor". My results: Anor sseems to be the word for ,,flame" in the Lord of the Ring story.Would fit.
We know that From Soft were influenced by many other games and movies so LotR does not seem too far away.
Anor Londo= Wild Flame?
Anyways, check out the Celtic gods, it was enlightening.
I also got some solid speculations on other parts of the game but right now I don't have the time to post it all so see ya and sorry for the bad structure.