Amlug Sigil

"Amlug Sigil" or the Dragon Dagger/Knife is an ancient weapon currently held by the Order of the Red Dragon.
Its precise origins are unknown, but the artifact was created when elves still ruled Sirion.
The weapon has the magical ability to store and enhance whatever spell is cast upon it (even if unsuccessfully). The strengthened spell is released when the blade cuts the surface of the target being or object.