League of Legends Lore Source? Where can I find it? How much is true?

Hello everyone, I am Leroyswish. I have been reading the constantly updated and fantastic source of knowledge, the League of Legends wiki. However, a lot of lore seems to be missing or incomplete; also, I'm not sure how much is true. I am usually unable to write up lore on my own characters, such as Zero or Thule, because I am unaware of the pre-established lore sources. Riot employees or fellow game players/writers, where can I find accurate and detailed sources on the lore and background of League of Legends?