HL-98 Hercules H21 is a fictional labor unit in Kidou Keisatsu Patlabor, a heavy industrial mecha used for construction and police-related support tasks. Rather than being a human character, it is a machine designation associated with the series’ realistic near-future setting. The Hercules H21 represents the kind of specialized work robot that exists alongside the Patlabor units, helping establish the world’s industrial and technological background. Its role is mainly as part of the setting’s machinery and equipment ecosystem.