AETHER is an ancient artificial intelligence located within the gas planetoid, Ragnarok. It is one of the most advanced machines in the known galaxy, reaching sentience, and is capable of turning other AI into sentient beings aswell.
AETHER is a massive artificial intelligence core, originally located within the mega-vessel, Polaris. AETHER is the most advanced artificial intelligence ever, being created eons ago by a race preceding the Protheans by billions of years. AETHER is not only in the center of Ragnarok but he has created it, using immense gravitational force and gases to hide itself from Reaper fleets looking to destroy the vulnerable core. As Ragnarok has begun to become filled with massive amounts of debris, it began building tours protruding from it's main core to the upper-atmosphere of the planetoid.
These nodes allowed AETHER to have contact with it's surroundings and whatever came near it. As time went on and AETHER was forgotten, it's power core began to weaken. It used what was left of it's power to build energy-absorbing panels and factories which would build guardian robots. AETHER would put itself into indefinite standby mode and transferred much of it's processing power to the node towers. Millenia later, a cargo ship carrying LOKI and YMIR mechs would crash into the planetoid. One of the node towers would sense their virtual intelligence and begin enhancing them to become sentient machines and the first inhabitants of Ragnarok.