Oblivion's Edge is a medium armor set. The 5-piece set bonus adds 129 Weapon Damage. When you kill an enemy, you fill an empty Soul Gem and heal for 1720 Health.
The Oblivion's Edge set is part of the base game. It drops in Vaults of Madness in Coldharbour. Each set item is bound on pickup. You can acquire medium armor, weapons and jewelry of this set in the Breton motif style.