The Pure Nail is a meleeweapon which can be swung above and below, as well as horizontally, depending on player input. Vertical attacks deal critical damage.
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."
Notes
Due to this weapon's fast animation speed but high attack cooldown, it works well for alternating between attacks with another weapon to increase damage output.
However, quickly inputting a different directional attack after an upward or downward attack cancels the cooldown of the first one, allowing for slightly better burst damage.
The Nail is unique in that the player can slash up and down as well as horizontally. Slashing enemies from above has a slight recoil, or "bounce." Attacking enemies from above or below is relatively safe.
This weapon's guaranteed critical hits when attacking vertically give it a big advantage in biomes with lots of platforms. The upward slash is also very useful against flying enemies.
The ability to attack while airborne above enemies offers a significant advantage against some bosses like the Hand of the King and the Concierge because few of their moves can counter it.
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.