Carbon Fiber

 is a relic material used in crafting.

Obtaining
can be gathered by:
 * Obtaining loot or post-level rewards for levels 1-75 in the Deepest Ruin if the player completes a level with a Rank S (level completed in less than one minute).
 * Commissioning the Civil Corps to run Middle, Lower, or Deep Levels of Ingall's Mine. Carbon Fiber will be delivered every time the Civil Corps complete the player's commission, even though is not shown in the item list on the Civil Corps' Commission Board.
 * Mining in Somber Marsh Abandoned Ruins as a rare scanned relic.

The most efficient and cheap way to obtain is fighting in the Deepest Ruin: there is a chance to get it as a reward for clearing any level between 1 and 75. If the player has the Loot skill and consumes Lucky Bean Jelly from the Vending Machine at the start of each floor of the Deepest Ruin, there is a chance to get quadruple (4x) the loot obtained.

The most expensive, though also efficient, way to obtain is by commissioning the Civil Corps. Marrying one of the Civil Corps members allows certain relationship perks to activate when commissioning the Corps: Arlo guarantees 50% more loot, Remington guarantees a 50% reduction in commission fees, and Sam guarantees commissions will be delivered in half the number of days.

The least efficient way to obtain is by quarrying in the Somber Marsh Abandoned Ruins, due to 's low spawn rate and the large amount of  needed.

Usage
is used in crafting late-game items. It can also be gifted.

Worktable
is a required ingredient when crafting the following item:

Assembly Station
is a required ingredient when crafting the following item:

Gift
can be given as a gift to other characters.