Unlocking the Torch Fighter node on the Destiny Board allows you to use the various Hunter off-hand weapons and their respective passive abilities below. The previous node required to unlock the Torch Fighter is Journeyman Hunter.
Torches are off-hands which usually complement an offensive main hand weapon, but can be used in various situations due to their versatile characteristic. They usually provide cooldown modifier and attack speed modifier.
Artifact Torches Weapons
You can view the required artifacts on the Artifact page.