GAT-X123 Fullauto Gundam (Conflicted Hearts)

The GAT-X123 Blaster Gundam was one of the Prototype Mobile Suits built by Morgenrote Inc. for the Earth Alliance on the Orb Union's Heliopolis Colony, it was designed as the Prototype Artillery-support Mobile Suit and has two batteries to that end - one for the Mobile Suit and one stored on back for "Agni Burner" Beam Cannon, it is piloted by Thomas Okumoto.

Design Features
The Blaster is described as the Twin of the Buster Gundam, having a similar look to the Verde Buster, and is designed more for Artillery Support for allies than all-out offensive carnage that the Buster is known for.

Trivia

 * Blaster is a common name for a long range weapon in many fictional series.