Pure Nail

The  is a melee weapon which can be swung above and below, as well as horizontally, depending on player input. Vertical attacks deal damage.

Location
In the Prisoners' Quarters, there is a chance for a lore room to spawn with a bench in it. When examining the bench, the nail drops. Picking it up will unlock it permanently.
 * "This place feels so... peaceful."
 * "I feel like sitting on it would be a great relief."
 * "It's good to be right."

Trivia

 * This weapon is a reference to the Pure Nail - the fully upgraded form of the main weapon in Hollow Knight.
 * The weapon's flavor text refers to one of the lines of the Nailsmith, the creator of the Pure Nail.
 * The location of the weapon is also a reference to the save point benches in Hollow Knight.