Let me quote it:
"Your quests for Dawnguard and the vampires will take you to several locations, and one of them is(light shines on the word, making it obscured), the plane player visited multiple times in Elder Scrolls IV. Unlike the fiery fields(light again obscured the information from the scan).
We are returning to Mehrune's Realm. Fact.
"Your quests for the Dawnguard and the vampires will take you to several locations, and one of them is a realm of Oblivion - the plane players traveled to multiple times in Elder Scrolls in Elder Scrolls IV. Unlike the fiery fields of that game, Dawnguard's piece of Oblivion has a ghostly, ethereal visual style. Dubbed the Soul Cairn, this haunting realm of trapped souls offers a change of scenery from the stark, Nordic surroundings of Skyrim."