Iron Ocean

An Iron Ocean (アイアンオーシャン, Aian Ōshan, also known as 鉄海, Tekkai) is a large body of liquid metal that appears in Black★★Rock Shooter DAWN FALL. Its concept is also briefly mentioned in Black★★Rock Shooter BEFORE DAWN.

Description
Iron Oceans were essentially special liquid metal manufacturing plants created as part of Artemis' plan to exterminate mankind from Earth. According to the Colonel, Dead Master, and Strength, Iron Oceans nested Arche nanomachines that could absorb all sorts of life and matters upon contact, and converted them into raw material for producing Unmanned Forces' machines. Gigantes machines would transport captured humans and feed them to the Iron Oceans.

Unbeknownst to the humans, the Iron Oceans' ultimate purpose was to supply the Moon via the Orbital Elevator with the liquid metal processed from humans, which would in turn be used for Moon Flake kinetic bombardment against the Earth to ensure human's extinction.

Iron Oceans were not exclusive to Artemis' machines; they were also home to various endemic living organisms. Isana would camouflage her ship by allowing such creatures to adhere to the ship's outer hull in order to safely travel on the Iron Ocean in Central America.

However, it was still dangerous for a human to dwell on an Iron Ocean, even with respirators on, as the surrounding air also contained very high concentration of Arche, and remaining for too long would lead to inevitable Arche poisoning.

History
Shortly after Luna Griffith's assassination, a dead man's switch was activated within Artemis, which removed the restrictions set by the Three Laws of Robotics among other changes. As a result, Artemis determined that existing information on human development was insufficient, and mankind should be wiped out and recreated, possibly in repetition, in order to gather enough relevant data. It planned kinetic bombardment from the Moon to ensure human extinction, but it first needed the necessary material to power such an attack, hence the Iron Ocean concept was born to convert captured human beings into liquid metal as a type of fuel.

The Iron Oceans spawned in various locations across the Earth after Artemis openly turned against mankind, and in addition to converting captured humans and producing Unmanned Forces machines, they also drastically transformed the surrounding ecosystems over time.

When the Orbital Elevator was complete approximately twenty years later, Artemis began supplying the Moon with human processed liquid metal from Iron Oceans all over Earth at great speed. At the same time, the Peacebuilding Forces noticed the Iron Ocean around the Orbital Elevator began to expand, whereas those elsewhere contracted or retreated underground. The artificial intelligence also instructed most Unmanned Forces machines to retreat into Iron Oceans, while reinforcing defense around the Orbital Elevator. The initial wave of Moon Flakes hit the Earth's surface approximately twelve hours after the Orbital Elevator's completion.