When Kitase was put in charge of "Final Fantasy VII", he and Nomura reworked the entire initial plot. Scenario writer Kazushige Nojima joined the team after finishing work on "Bahamut Lagoon". While "Final Fantasy VI" featured an ensemble cast of numerous playable characters that were equally important, the team soon decided to develop a central protagonist for "Final Fantasy VII". The pursuit of Sephiroth that comprised most of the main narrative was suggested by Nomura, as nothing similar had been done in the series before. Kitase and Nojima conceived AVALANCHE and Shinra as opposing organizations and created Cloud's backstory as well as his relationship to Sephiroth. Among Nojima's biggest contributions to the plot were Cloud's memories and split personality; this included the eventual conclusion involving his newly created character of Zack. The crew helped Kitase adjust the specifics of Sakaguchi's original Lifestream concept.