Masato Hirano (平野 正人, Hirano Masato; born November 16, 1955) is a Japanese actor, voice actor and narrator from Iwate Prefecture who works for Aoni Production. Among his other roles, he has performed the characters Ippon-Matsu and Topman Warcury (One Piece), Zaku (Fist of the North Star) and Kinnikuman Big Body (Kinnikuman: Scramble for the Throne).
Source: “Masato Hirano (voice actor)”, English Wikipedia (CC BY-SA 4.0), excerpt