Reaper (Dawnguard)

The Reaper is a secret boss in The Elder Scrolls V: Dawnguard, located in the Reaper's Lair, which itself can be found in the Soul Cairn. To fight it, one must place at least three Reaper Gem Fragments on its altar to summon it. The Reaper itself is a giant, ghostly masked figure that wields a war axe and can spit slime like the Afflicted. When defeated it drops three empty Black soul gems.