General Information
I thought of a wonderful present for you...

Hair: Silver, waist-length
Eyes: Bright green, possibly influenced by mako energy
Age: 20 years old at the start of Crisis Core; 27 years old in Final Fantasy VII
Date of Birth: December twenty-five
Height: 185 cm (6'1")
Occupation: SOLDIER 1st class

Alternate name: The Man in the Black Cape, One-Winged Angel

Others: Slightly aquline nose, angular chin and narrow face, high cheekbones, pale skin, thin lips, heavily muscular.

Background
You have never even thought about it.

Sephiroth was known throughout Midgard as the finest SOLDIER of Shinra. Of a kind and amiable nature, he was nonetheless dedicated to his job and was quick to earn the respect of many of his comrades. Sephiroth had always known that he was special—but he never knew just how much. He knew nothing about his parents, save that is father was never there, and that his mother was named Jenova.

Encountering monsters cocooned within the bowels of the mountains surrounding Nibelheim however, made him wonder—one of the tanks was labelled "Jenova", the same name his mother had. The mutated monsters within the cocoons had once been human. Had he, Sephiroth, been created the same way?

Then there was a time of madness. The library at the Shinra mansion offered some possible answers, and after three days spent poring over the volumes, Sephiroth had reason to believe that he was not human after all, but a Cetra. The Cetra were sacrificed to save the planet and the ancestors of humanity, who hid and did nothing to save them. Jenova was found thirty years ago and thought to be the last of her kind, and kept by the Shinra as part of the Jenova projec, tasked with imbuing humans with the power of the Ancients. Humanity took that which was the Cetra's, and it was only fair that he, Sephiroth, of Cetra heritage, and his mother Jenova, take back what was rightfully theirs, and rid the world of the humans.

Sephiroth journeyed back to the Mako reactor at Nibelheim, but never returned. Until the events of Final fantasy Seven, his whereabouts were unknown.