Sephiroth is the main antagonist of Final Fantasy VII, and one of the major villains of its extended universe. A prototype SOLDIER and the strongest alive, Sephiroth is initially revered for his strength and hailed as a hero, until he learns and misinterprets his origins. Believing himself as the last of the Ancients, Sephiroth enacts a vendetta against mankind, with the ultimate goal of becoming a god and controlling the planet. Sephiroth's goals later include defeating Cloud Strife, who has consistently foiled his plans. To this end, Sephiroth is frequently depicted as Cloud's archnemesis.

Sephiroth is arguably the most popular villain of the Final Fantasy series. Sephiroth, in all his appearances, wears a long black coat with silver pauldrons, black boots, and black clothing underneath. The top of his clothing underneath his uniform is split to reveal his chest, covered by crossing leather straps. His hair is long and silver, a sharp contrast to Cloud Strife's blond spikes, with his bangs parted to either side of his face. Beyond his clothing and hair, Sephiroth is known for his green cat-like eyes and the Masamune, his seven-foot long katana that he is rarely seen without. Sephiroth's typical battle stance with the sword is to hold it over his left shoulder, and he usually wields the Masamune two-handed, presumably to increase the force of his strikes as he is capable of using it with one hand. In later appearances he has a single black wing emerging from his right shoulder.

Sephiroth's personality is one of cold ruthlessness. Prior to his madness, he was not particularly anti-social, as he has friends in Crisis Core Final Fantasy VII and willingly tells Zack and Tifa about Mako and Materia on Mt. Nibel. All the same, his cold exterior and professional attitude turn people away. He is very intelligent, and is respectful to those he deems worthy - he considered Professor Gast a great scientist, but looked down on Professor Hojo and described him as "a walking mass of complexes". Sephiroth is confident to the point of arrogance, but as the strongest SOLDIER alive it could easily be argued he has the right to be. Well-spoken and somewhat graceful, Sephiroth is universally calm, collected, and in control. He can be frustrated and caught off his guard, but this rarely happens.

Besides Final Fantasy VII, Before Crisis, Crisis Core, and Advent Children, he also appears in Dissidia Final Fantasy on the side of Chaos and Kingdom Hearts series as an optional boss.

The protagonist of Suikoden II is a soldier of the Highland Army's Unicorn Youth Brigade and 16 years old at the beginning of Suikoden II. He wields a tonfa and becomes the bearer of the Bright Shield Rune.

As a child, Riou had been left an orphan by wars and he and a girl named Nanami were adopted by a hero named Genkaku. He grew up in a small Highland town called Kyaro and eventually became friends with Jowy Atreides. Along with Nanami, they would train under Genkaku to become strong fighters. Riou and Jowy went on to join the Unicorn Youth Brigade.

When the Youth Brigade is slaughtered by Luca Blight as an instigator for war, Riou ends up separated from Jowy and captured by a band of mercenaries under the command of Viktor. Jowy attempts to rescue him, but the boys were both caught. After several attempts, they manage to escape and eventually reunite with Nanami. Their reunion is fleeting as Riou and Jowy are arrested soon afterwards by their former captain. They are rescued by Viktor and Flik, the boys and Nanami escape from Highland and aid Viktor by recruiting more mercenaries.

During the Dunan Unification War, Riou and Jowy are approached by the strategist, Apple, who intends to approach Viktor and provide him information concerning the plans of the Highland Kingdom. After recruiting Tsai and witnessing the insanity of Luca Blight, Riou and Jowy join the Dunan Unification Army. Riou becomes the leader of the Dunan Unification Army after defeating Solon Jhee. However, he soon finds that he must fight against Jowy after Jowy marries Jillia Blight and becomes Commander-in-Chief of Highland Kingdom's army. Both young men end up inheriting half of the Rune of Beginning and must end the war before their friendship is torn apart forever.

Zack Fair is a non-player character from Final Fantasy VII and the main protagonist of its prequel, Crisis Core Final Fantasy VII. The wielder of the Buster Sword before Cloud, Zack received the Buster Sword from his predecessor Angeal. Zack is a 1st clas$ SOLDIER and is Cloud's best friend during their time working for Shinra. However, after Sephiroth goes insane, they become test subjects to Professor Hojo, and Zack ultimately sacrifices himself to save Cloud's life. He is also Aerith Gainsborough's former boyfriend.

Zack acts as the protagonist of Crisis Core: Final Fantasy VII. He works as a subordinate under his close friend and mentor Angeal Hewley.Through various events, Zack falls in love with Aerith and befriends Cloud, Tseng, Cissnei, and Sephiroth. Zack is assigned to accompany Sephiroth and two grunts, one being Cloud, on a mission to Nibelheim to find the cause of a Mako reactor malfunction. While there, Sephiroth discovers his supposed origins and goes insane. Both Zack and Cloud engage him in battle, and Sephiroth is eventually thrown into the Mako reactor by Cloud. However, Zack and Cloud are too injured to continue on, and taken by Hojo for experimentation. After being experimented on for four years, Zack escapes with Cloud and begins a journey to Midgar. On their way, Zack is intercepted by Shinra armed forces. Zack is shot continually in the chest by a soldier. While dying, Zack gives the Buster Sword to Cloud, telling him to live out his own life as well as Zack's, that Cloud is his living legacy. As Cloud stumbles off towards Midgar, Zack is pulled into the lifestream by Angeal, and wonders if he had become a hero.

In Final Fantasy VII, Zack only appears in flashback sequences, which portray him as almost identical to Cloud Strife in physical appearance except having black hair. When strung together, the sequences explain a great deal about Cloud's past and his connection to Sephiroth, the game's arch-villain.