The Dom was the next mobile suit developed after the Zaku II, and was focused for ground combat on Earth. It was used in the One Year War by the Zeon forces. Carrying a Heat Saber, and a 880mm Rattem Bazooka, and a Scattering Beam cannon in its chest.
Shortly after the war began, Zeonic forces realized that the formerly brilliant Zaku 2 suits were woefully inadequate for groundbound combat. Both because they weren't manuverable enough and were too heavy. To fix the situation the Zeon forces bean to develop this, the MS-09 Dom. The massive legs and 'skirt' concealed powerful jet engines that made the Dom hover, not walk. The performance of the Dom was so much greater than the Zaku 2 (240kph hovering speed compared to 99kph Zaku running speed) that the Dom was the new standard issue suit.
In terms of armament the Dom was just as versatile as its ancestor, able to be armed with everything the Zaku 2 could be armed with and more. The addition of a 360 mm bazooka could destroy a federation GM in one shot. Later on, the addition of the 880mm Rakten Bazooka meant that a single Dom could destoy most anything in one shot. For melee combat the Dom was equiped with a heat saber, very similar in design to the federation beam saber.