find aNightmare Sigil. Your best chance for getting one of these is completingWhispers of the Deadfor the Tree of Whispers to earn a loot cache, since these have a chance of dropping Nightmare Sigils. When you've got one, simplyuse the sigil in your consumables to activate the dungeon. ...
You will need to collect nine Distilled Fear, which can be combined with 250 Sigil Powder--collected from scrapping Nightmare Sigils--at an Occultist to create a Glacial Fissure Nightmare Sigil, which will always be Tier 31. Take that to Glacial Fissure in Fractured Peaks to take on the ...