The Astral Fang is a Hardmodebroadsword that is dropped by the Lunatic Cultist. While it does not possess any notable attributes initially, after defeating 50 enemies with it, it will become greatly empowered. While empowered, its power will increase by 75%, bringing the base damage of the sword from 120 to 210, and it will gain additional effects based on whether it was empowered during the day or the night. These effects will last until the time of day changes.
This item is a reference to The Elder Scrolls IV: Oblivion. Like the Astral Fang, the Dawnfang or Duskfang is a blade that gains fire or frost-based properties depending on the time of day, as well as utilizing an empowering system based on defeating enemies.