The ASW-G-29 Gundam Astaroth is a mobile suit introduced in the manga Mobile Suit Gundam IRON-BLOODED ORPHANS Gekko. It is piloted by Argi Mirage.

The Gundam Astaroth is one of the 72 "Gundam" Frames produced and used in the Calamity War, roughly 300 years ago. It is also one of 26 remaining Gundam Frames that survived the Calamity War and reported to be operational. The Warren family, a family affiliated with Gjallarhorn, owned the Gundam Astaroth but was forced to sell its armor and equipment when their financial situation went bad, with the suit's Gundam Frame eventually acquired by Tanto Tempo's Daddy Ted. 

The Astaroth was then restored to operational condition by fitting its frame with a mix of parts from other mobile suits, and an example of this is that its left forearm armor and left shoulder armor are from a UGY-R38 Spinner Rodi. The two side waist armors are called Boost Armor, which has a wide range of movement and assists in the attitude/posture control of the mobile suit since the Astaroth's asymmetry affected its center of gravity.