F

is a Kumogakure shinobi.

Appearance
F has short, spiky brown hair, and sported a small goatee. Attire-wise he wears the standard uniform of Kumogakure shinobi along with his village's forehead protector.

Fourth Shinobi World War: Confrontation
During the Fourth Shinobi World War, F was attacked by a White Zetsu Army clone on the battlefield and was later impersonated by this clone. It is unknown if the real F is still alive.

Trivia

 * Like many Kumo ninja, his name is the Japanese pronunciation of an English letter, in this case "F".

F F F