Sephiroth was designed by "Final Fantasy VII"s character designer Tetsuya Nomura. His name came from the Kabbalah, in which the ten sephirot on the Tree of life represent the ten attributes through which God reveals himself. His character existed from the earliest stages of development, as originally, Nomura thought that the game's plot would deal exclusively with Cloud Strife pursuing Sephiroth, who was always the game's main antagonist. Nomura wanted Sephiroth to appear early in the game, and then have the plot dealing with the protagonists following him, so that gamers would not meet the final boss until extremely late in the game. Sephiroth was initially going to be Aerith Gainsborough's sibling, as indicated by their similar hairstyles. Later, however, he was changed to Aerith's past love, whom she would remember upon meeting Cloud. This character was then changed to Zack Fair, however, and Sephiroth’s prior relationship with Aerith was dropped. In early drafts of the game, Sephiroth's personality was already brutal and cruel, with a strong willed and calm ego. He was to suffer from Mako addiction, resulting in a semi-conscious state as a result of high level exposure to Mako energy. Sephiroth was also intended to manipulate Cloud into believing that he was a creation of Sephiroth's will, but this aspect of the story was later abandoned. In another excised scene, when Sephiroth's physical body is first seen in the Northern Crater, it was to be female. Yoshitaka Amano, who had handled character illustrations for previous "Final Fantasy" titles, noted a contrast between Cloud, a "young, passionate boy", and Sephiroth, a "more mature and cool" individual, as "intriguing", though not unusual as a pairing. Jason Greenberg, the only artist working on the original PC port, recalled a crash bug that happened during Sephiroth's technique. Near the end of the development cycle, many team members were done with their work and simply helped test the game as much as possible. Greenberg spent nearly 24 hours playing that one battle during development.