Prior to the events of the anime, three factions—the Garan Army, the Kiba Army, and the Aira Army, battle for total dominance of Machine Island. The island is basically a prison, isolated from the rest of the world. The island contains a vast amount of resources, allowing the three factions to create an infinite supply of giant robots for their respective armies. The world government learns that the island's power reactor has become unstable and will explode within 66 hours, destroying all of life and Earth itself. The government sends the Death Caprice squad, composed of mercenaries Ken Kaido and Ryo Magami to solve the issue, along with their giant robot Mazinkaiser, but was that a good idea?

The World as we know it has been torn apart shattered by a series of natural disasters that have turned civilization into a brutish nightmare of survival and has left whole cities buried beneath the Earth. It's now a lethal and chaotic place, a place where only the strongest and most savage remain alive. The strongest of them all is a giant warrior known as Violence Jack… Violence Jack tries to avert a civil war brewing among the wretched inhabitants of a subterranean metropolis called Evil Town. Based on a character created by manga horror specialist, Go Nagai. (Source: AniDB)

Zwei was an ordinary person, until one day, while walking the streets a night, he witnessed a brutal assassination. He managed to avoid the sniper, a young girl named Ein, but was soon captured, and had the memories of his former life erased. He is spared death only by accepting a condition: to train to become an assassin alongside Ein. Now, he must find a way to free himself from this shady world and reclaim his life once again. (Source: ANN)

2022: A future war has raged for decades between the few human survivors and an endless army of machines. 1997: The AI known as Skynet gained self-awareness and began its war against humanity. Caught between the future and this past is a soldier sent back in time to change the fate of humanity. She arrives in 1997 to protect a scientist named Malcolm Lee who works to launch a new AI system designed to compete with Skynet's impending attack on humanity. As Malcolm navigates the moral complexities of his creation, he's hunted by an unrelenting assassin from the future, which forever alters the fate of his three children. (Source: Netflix)