GAIA would utilize HEPHAESTUS to design, manufacture, and deploy any machine to ensure the project's completion. The machines would then be distributed for use by the other sub-functions. This means that - apart from the Faro robots (Corruptor, Deathbringer, and Metal Devil) - all machines are part of the GAIA project. The core log found when overriding the last Cauldron reveals that HEPHAESTUS is responsible for the derangement of the machines.
Up to the start of the derangement, the HEPHAESTUS sub-function seems to have worked accordingly. However, HEPHAESTUS eventually deemed humans a threat to its creations and started crafting more dangerous machines, such as the Thunderjaw.
- HEPHAESTUS is based on the Greek god of metalworking of the same name.