Whetstone Knife and Whetblades in Elden Ring are unique items that unlock the option of adding Ashes of War as well as different affinities to weapons and shields. There is one 'basic' whetstone knife and five whetblades available in the game. They can be used to change a weapon's affinity when adjusting their Ash of War at a Site of Grace.
Whetstone Knives
Locations on The Lands Between
1
Whetstone Knife
It's in a chest located in the basement of the ruins. Item Effect: Can add new battle arts and affinities to weapons.
2Iron Whetblade
In the room you can get to as long as you have one Stonesword Key. Affinities: Heavy, Keen, Quality.
3Glintstone Whetblade
Affinities: Magic, Frost.
4Red-Hot Whetblade
Affinities: Fire, Flame Art.
5Sanctified Whetblade
Affinities: Sacred, Lightning.
Locations on Undergrounds
6Black Whetblade
Affinities: Poison, Blood, Ocult.
