Sentoki

is one of the young monks-in-training at the Fire Temple.

Hidan and Kakuzu Arc
Sentoki was away when Akatsuki members Hidan and Kakuzu attacked the temple. He returned immediately after, finding the temple in ruins and the Akatsuki members as they were just about to leave. He then subsequently went to Konoha to notify them of the attack and requested for help.

He is one of only four known monk survivors in the attack, along with Bansai, Zenza, and Sora.

Trivia

 * Sentoki's name means "a thousand hours" or "a thousand times".