Sephiroth (?????, Sefirosu?): Sephiroth is the main antagonist, he's known to be the most powerful member of SOLDIER ever, and rose to a prominent rank at an early age. After a traumatic incident in which he learned of what he assumed to be his true origins, he left SOLDIER and indeed civilization altogether with plans to become a god-like power by wounding the Planet with Meteor and absorbing the entirety of the Lifestream sent to heal the damage. He manipulates Cloud (and the party, by extension) over the course of the game, as well as killing Aeris.

Sephiroth is also a member of the party for a very short period (during a flashback sequence), however he is totally controlled by the computer during combat and the player cannot change his equipment and materia. He is personified by his primary weapon; the powerful Masamune sword which he uses to inflict large amounts of damage.

Cloud destroys Sephiroth at the end of the game; however, he returns for a short time in the sequel Final Fantasy VII: Advent Children where he is reborn through the body of Kadaj and subsequently defeated once again by Cloud. He warns Cloud that he will "Never be a memory".

Sephiroth was injected with Jenova cells a short time after his conception, making him arguably her direct offspring, though he was originally the unborn son of Lucrecia and Hojo. He believes that his mother is Jenova because that is what Hojo told him; it is doubtful he knows that Lucrecia even exists.