In the novel, Gaea creates a sword, Thyroros, the PortalBearer, from Earthsteel, a metal forged only in the First Fires. Just what is this mystic metal that Mother Earth alone forges, and how do the First Fires play a role in the molding of such a metal?
In the world that encompasses TASK FORCE: GAEA, Khaos, the cloud-like and ethereal primordial being from whom all life sprung, brought forth on her own such entities as Gaea, Nyx (Night), Erebos (Darkness), Aether (Upper Air), Hemera (Light), and the Moirae (Fates). After bringing the other Protogenoi, or Primordial Ones, into existence (she herself being the first one), Khaos burst into an all-consuming flame, becoming the First Fires of creation. Gaea took her mother's creative spark within herself, hiding it so far within herself that no god or mortal would find it. It was from this sacred forge that Gaea created Thyroros. By doing so, this substance was tempered with the same energy that shaped the cosmos, making anything heated within it impervious to harm by anything forged thereafter in any other flame. Only a weapon of the same origin could damage the sword, and Gaea protected her mother's remains with a vengeance. Not even Hephæstos can work metal in such a forge without the guiding hand of Gaea.
Before the Titans emerged, Gaea made the holy raw material from which would eventually come the substance know as Earthsteel, a crude translation of the original name that hearkened from an unspoken language only the Protogenoi know. Mother Earth taught Hephæstos how to create another form of Earthsteel, using less divine fires, that would adorn the halls and armories of Mount Olympos.
Sharpened to a razor edge, an Earthsteel blade can sever a marble column with barely any pressure, leaving no jagged edge on the stone whatsoever. Heated to different temperatures (of the First Fires or Olympeian forge fire), the metal can take on different hues, from a soft gold to a shiny silver to a dark steel.
Earthsteel appears in TFG: Finding Balance, and will show up again in TFG: (the sequel). Stay tuned for more developments.