Tetsu

is a shinobi from Kirigakure that fought during the Fourth Shinobi World War.

Shinobi World War Arc
Tetsu had his chakra drained by a White Zetsu clone, allowing it to impersonate him in order to assassinate his comrades. It is unclear whether the real Tetsu is alive or not.

Trivia

 * "Tetsu" (鉄) means "iron".