Stormfang is a lightning-charged greatsword from the Dragonborn add-on, carried by a Reaver Lord – and one of the few unique weapons that respawns.
How to get it
Defeat the Reaver Lord at Brodir Grove on Solstheim and take it from him.
Enchantment
Target takes 30 points of shock damage and half as much magicka damage. Unlike most unique weapons, it can be disenchanted to learn the effect.
Stats
17 damage, 17 weight – it looks just like a normal steel greatsword.
Smithing
Steel Ingot with the Arcane Blacksmith perk.