Cloud Strife

Later, as the game proceeds, it is revealed that after Zack Fair’s death, Cloud loses his memories and his mind gets suppressed by the Jenova cells within his body, making him believe that he is Zack. (The cells taking control over his body (as a result of intensive geostigma) can be seen in Advent Children, too, the moment Cloud stands before Zack’s grave and in the church, making him lose consciousness and fall to the flowerbed alongside defeated Tifa.)

A major part of the original FFVII is devoted to the subject of Cloud regaining back his memories and understanding who he really is.

Cloud seems to be avoiding contact with his family as he believes that he is of no help to anyone. He still blames himself for being unable to save Aerith Gainsborough from being killed by Sephiroth. He is now also infected by geostigma, so he gives up all hope as there is no cure and is expecting to die. He, nevertheless, manages to regain self-confidence and faith before he defeats the memory of Sephiroth once more. His Geostigma is also cured in Aerith’s Church, with the power of the lifestream within the rain and water.

Cloud is also the only successful “Sephiroth Clone,” in other words, the inheritor of pure S Cells. He was unknowingly injected with them by Hojo of Shinra’s Science Department soon after the Nibelheim Incident.