Zed's Lore has it that, he and Shen were once of the same Temple and were Students. However, Zed and Shen took different paths. Like many stories, there is the good guy, and the bad guy. The one that stays and learns the True Way in Balance, and the other who seeks for something more, The one who instead of "Balancing", turns to "Destroying". Zed eventually overthrew the Temple in which he was banished from, and made it the Training Grounds for The Order of the Shadow, which he was the leader of. Now that he has proven himself to his Students and to the Temple, he has decided to join the League of Legends to let everyone know, that he is the One True Ninja.