Cloud Strife

Today, We're gonna go into full detail and the history of Cloud Strife. The Legacy of Zack Fair and the successful experiment of  Prof. Hojo.
In Final Fantasy VII, due to the combined effect of Mako poisoning and the influence of Jenova's cells in his body, Cloud unknowingly holds a fake persona created by the Jenova cells mixing his memories of Zack's personality with the somewhat cocky and selfish attitude he believes a SOLDIER 1st Class would have. However, during the game events he eventually restores his original personality, and shows genuine concern for the Planet's fate, a sharp contrast to his persona at the start of the game where he claimed he did not care about the Planet and only agreed to help AVALANCHE for the right price.
In Advent Children and many related appearances, Cloud is a much more somber and dark character, tormented by guilt over what he perceives as his past failings; being unable to prevent the deaths of Aerith Gainsborough and Zack Fair. The final straw was when he contracted the terminal Geostigma plague, which added to his feelings of helplessness. Deciding to distance himself from his friends and live alone, he tries to keep his affliction secret so as not to cause further grief.
However, during the film Cloud faces his past both metaphorically and literally, with Sephiroth's rebirth, his visions of Aerith and shows of loyalty from the friends he tried so hard to let go. These events allow him to forgive himself for the deaths of Zack and Aerith and move on, although it is unclear what this ultimately means in terms of his personality and lifestyle. However, the mere fact that he is present to aid his old allies shows that he has indeed moved on in his life.
In Crisis Core, Cloud is depicted as a rather shy, but more upbeat person who idolizes both Zack and Sephiroth. However, when Sephiroth burned down Nibelheim and badly wounded his friends Zack and Tifa Lockhart, Cloud does not hesitate to avenge them by hurling the madman to his apparent death whilst himself being impaled with the Masamune.