- "Absurd. Defeating me is meaningless. You know that more than anyone, Cloud. No matter how many times I fall, your darkness keeps calling me back!"
- —Sephiroth to Cloud
Sephiroth is the embodiment of Cloud's darkness. He, along with Cloud, Tifa, Aerith, Yuffie, Zack, and Cid, originate from the Squaresoft game Final Fantasy VII, where he served as the main antagonist. Sephiroth is the only Final Fantasy villain so far to appear in the Kingdom Hearts series.
While Terra is in Olympus Coliseum, Zack reveals that he aspires to become a hero like "another", referring to Sephiroth. Later, after Master Xehanort's defeat, a black feather falls before Zack as he watches Hercules train, hinting at Sephiroth's presence.
Sephiroth appears within the Platinum Match at Olympus Coliseum, and after a difficult fight, Sora narrowly seizes victory. As Sora leaves the stadium, Cloud enters. Sephiroth invites Cloud to turn to the darkness, but Cloud refuses, launching a high-speed aerial battle whose outcome is not seen.
Kingdom Hearts IIEdit
Right before the invasion of Hollow Bastion, Cloud warns Sora and company about Sephiroth, and his ways of the darkness. Later, as Sora exits the castle to go help defend against the invasion, Sephiroth appears. He asks about Cloud's whereabouts, and although Sora says nothing, Donald and Goofy retort that Cloud realizes that Sephiroth is the manifestation of his darkness. Seeing that Cloud is becoming enlightened and desires to fight him, Sephiroth takes his leave.
During the battle, Cloud is surrounded by Heartless, but Sephiroth intervenes, defeating them all in one slash. Cloud intends to defeat his nemesis to escape the darkness, but Sephiroth only replies that Cloud will never be able to do so, and will always cower in the light. Cloud vehemently denies his dark half's claims, but Sephiroth is undeterred, and leaves just as Tifa arrives.
After the Master Control Program is defeated, Sora encounters Sephiroth at the Dark Depths at Hollow Bastion. The villain again asks about Cloud, but Sora and his companions do not reveal anything. He then inquires about Sora, Donald, and Goofy's identities, but again, they refuse to answer. Sephiroth then notices Sora's Keyblade, and attacks, intending to test Sora's power and that of the Keyblade. Even though Donald and Goofy are with Sora when he confronts Sephiroth, they do not fight with him, since Sephiroth only wishes to battle the Keyblade master. Sora appears to overcome him, but Sephiroth just shrugs off the battle. Sephiroth compliments Sora on his skill with the Keyblade but says that Cloud is the only one that can "eliminate him". Sephiroth then tells Sora to find Cloud so that they can settle their feud.
Cloud arrives later, and they initiate a battle, with Sephiroth desiring to draw Cloud into the darkness. However, Tifa protects Cloud, saying that Cloud does have light in him, and that, even if he doesn't, then he just needs to be surrounded by light. Nevertheless, Sephiroth and Cloud start off for another battle, and after Tifa's intervention, Cloud glows in light, surprising Sephiroth and letting his guard down. The two disappear in a brilliant flash of light.
Although several characters in the Final Fantasy series appear in the Kingdom Hearts series, Sephiroth is the only villainous Final Fantasy character to appear as of recently.