After defeating the Dragun, you'll gain access to the Bullet That Can Kill The Past. To use it, you must first assemble its components: the Planar Lead, Arcane Gunpowder, Prime Primer, and Obsidian Casing. These items are found on specific floors and must be delivered to the Blacksmith in the Forge. Once assembled, you can use the Bullet to travel back in time and face your character's personal past boss.
