Also known as: ブグ, ブグ(THEORIGIN)
MS-04 Bugu
A Zeon Mobile Suit from The Origin. It was Zeon's first combat-ready MS, and a predecessor to the Zaku line.
Share's it's numerical designation with the Prototype Zaku from Gundam MSV, and it's name with the Bugu (G-Saviour) from Gundam G-Saviour.