Sentomaru is a character from the anime and manga series One Piece. He is known as the bodyguard of Dr. Vegapunk and the commander of the Marines' Science Unit. Sentomaru is characterized by his large build, distinctive armor, and a giant axe that he wields with great skill. His loyalty to the Marines and his role as a protector of Vegapunk's inventions make him a significant player in the series. Sentomaru's confident and sometimes brash personality often leads to confrontations with pirates, including the Straw Hat Pirates.