Harkon’s Sword is the golden blade of Lord Harkon, master of the Volkihar Clan, from the Dawnguard add-on. It looks like a Blades sword with bats on the guard – and its enchantment only wakes up in the hands of a vampire.
How to get it
Loot it from Harkon’s remains after defeating him in Kindred Judgment. With the Misdirection perk you can technically pickpocket it earlier, but its high value makes that very hard.
Enchantment
If you’re a vampire, each hit absorbs 15 points of health, magicka and stamina, and the screen darkens slightly with every strike. If you’re not a vampire, it’s just a fairly weak sword.
Is it worth using?
The base damage is low at 8, but the triple absorb keeps a vampire build topped up during power attacks, bashes and spellcasting. It burns through charges fast, so carry filled soul gems – or wear gear that lowers Destruction costs, which stretches the charges further.
Smithing
Steel Ingot at a grindstone (Arcane Blacksmith); benefits from Steel Smithing.