Fire Rune

The Fire Rune is an item used primarily as ammunition for staves.

Rune Shrine
Using Unpowered Runes or Charged Runes on a Rune Shrine that is centered on a Fire Rune Shrine, will convert those Runes into Fire Runes. The player can only convert Runes into Fire Runes if their Runation level is 8 or higher.

Mob Drops
Fire Runes can be obtained as a drop from the following mobs:
 * Baroness
 * King BamBamBam
 * Nethengeic Wither
 * Red Guardian
 * Undead Troll

Rune Box
Fire Runes can be found when opening a Rune Box.

Rune Randomizer
Using Unpowered Runes or Charged Runes on a Rune Randomizer has a chance to convert them into Fire Runes.

Ammunition
Fire Runes are required as ammunition for the following Staves: Additionally, Runic Sword can consume Fire Runes when attacking to ignite mobs on hit.
 * Ember Staff
 * Fire Staff
 * Firefly Staff
 * Firestorm Staff
 * Sun Staff

Banner Pattern
Crafting a Fire Rune with a vanilla Banner and a dye will give the Banner a pattern that resembles the Fire Rune's symbol.

Rune Templar
Using a Fire Rune and Runic Energy on a red Rune Templar will activate it. This will not consume the Fire Rune, only the Runic Energy.