Promethean Spark (Bot Fuel)

The Promethean Spark is the fuel that keeps your Daedalus Construct mining bot running.

Each blaze-powder spark powers one bot for one hour. Click a spark into the Construct's GUI to feed it, and stockpile a few if you want it churning through the Mines while you're away.

Where to get it: wraiths in Forgotten Polis are the source — every wraith tier drops sparks, and the higher tiers drop them in bigger stacks, so an endgame wraith farm is what keeps a cell full of bots fed. Bosses no longer drop them.