Sephiroth is the main antagonist of Final Fantasy VII. Sephiroth is depicted as Cloud Strife's archenemy, and is seen as a symbol of Cloud's troubled past that haunts him. Sephiroth is a former renowned SOLDIER, who became twisted.

Before his fall from grace, Sephiroth was one of the most lauded success stories of the Shinra Electric Power Company's SOLDIER program. His successes in the field of battle during the conflicts surrounding Shinra's bid for global domination led to his status as a celebrity war hero and the poster boy for both the Shinra Military and the company's SOLDIER program. Learning of his true origins drove him insane, causing him to be driven by a desire to destroy the world.

Sephiroth is briefly a party member during a flashback, and is both the penultimate and the final boss.

In 2020, Sephiroth was announced as a DLC fighter for Super Smash Bros. Ultimate. He is the second fighter from the Final Fantasy universe to be playable in the game, following Cloud. His announcement occurred at The Game Awards 2020 and he was released in December 17, 2020 during the Sephiroth Challenge event, before being actually released on December 22, 2020. Like Cloud, Sephiroth stills speaks Japanese in all versions.