Tomb Raider (2013) · Bow upgrade
Fire arrow
Fire arrows add a special bow mode and are obtained automatically as the story progresses.
How it works
Namu lists fire arrow as a story unlock, with no salvage requirement in its upgrade table, and says it adds fire arrows. The passage says fire arrows can later be converted into napalm arrows and share their ammunition count with regular arrows. It does not specify the story event that grants them.
Read the supporting references
Check the edition and source version for patch-specific details. Guide methodology.