The Death Army (デスアーミー Desu Amī) are a series of cards that include "Death Army" in its card name exclusive of Nova Grappler clan. They were first introduced in Booster Set 3: Demonic Lord Invasion, and later it gets a huge support in Extra Booster: Infinite Phantom Legion.
This deck mainly focus on resting of your rear-guards during the main phase order to gain huge Power, and then stand them back during that main phase.
Who are the Death Armies?
The generic name for Mechanical Soldiers that were produced with the aim of creating an immortal warrior that will never be defeated. The machines are all completely controlled by A.I. (Artificial Intelligence), thus the buyers can participate in matches, without the need of the buyer to participate directly in it. Because of this, it is hugely popular within the wealthy peoples, and has contributed to the increase in participants in the Nova Grapple because the bar (Conditions to participate) has been lowered. However, there had been a lot of mysterious accidents and incidents revolving around the "Death Armies", such as the theft of the frozen prototype, etc... Because the many dark rumours about the manufacturer, this series is also very famous in the side behind the curtains.