Forge Fuel

Forge Fuel is the coal-based currency that keeps a cell Forge running.

Right-click a placed Forge to load fuel into it, and each unit burns down over time to generate Ancient Energy at the forge's tier rate — the rate scales up as you climb from LOW through VIP. A single forge holds up to 256 fuel, so topping one off lets it produce passively while you're away. It's a bread-and-butter part of cell income alongside generators.

Where to get it: a common drop from Erebus Pit guard kills, caravan and escort loot, and a regular fill in lootboxes and crates.