Sephiroth is a fictional character and main antagonist in Square’s role-playing game Final Fantasy VII. He was designed by character designer Tetsuya Nomura and is characterized as a tall man with long silver hair. His appearance was intended to contrast directly with that of the main character, Cloud Strife. Sephiroth’s English-language voice actor is Lance Bass in Kingdom Hearts and George Newbern in all other appearances. His Japanese-language voice actor is Toshiyuki Morikawa, although Shin-ichiro Miki voiced the character in Ehrgeiz.

In Final Fantasy VII, Sephiroth serves as the primary antagonist who attempts to become a god by absorbing the planet’s energy. He has also made appearances in the Compilation of Final Fantasy VII, Kingdom Hearts series, and Dissidia: Final Fantasy.

Sephiroth has been well-received within the video game community due to his complex motivations and his iconic appearance, particularly his extremely long sword, Masamune. As a result, he is regularly featured in top positions on many “best villain” lists and character polls assembled by game publications and fans.
From Wikipedia