Dark Souls and its Artorias of the Abyss DLC are the focus of an article-style interview with game director Hidetaka Miyazaki at IGN. In the course of the article, From Software's developer reveals several lore and design snippets, including the purpose of the mysterious pendant starting gift:
When Dark Souls first came out, an answer Miyazaki gave in a Famitsu interview said he'd choose either nothing or a pendant for his starting gift in Dark Souls. The pendant, which has no in-game function, became a focal point for the wilder elements of the community, and the centre of every conspiracy theory going.
I ask Miyazaki whether Manus is a little dig at the series' more obsessive players. (That is a very interesting consideration,) says the devilish fox. (But I suppose I did not include the meaning.) And as for the original pendant speculation, brace yourselves Dark Soulers for Miyazaki's final word: (When it comes to the pendant, I actually had a little bit of an intention to play a prank.)