Infernal Fear Device ...... (Diablo 3)

Can't knock out the hellish fear device that leads to the Ãœber Diablo, who has a heart of evil for an amulet. More precisely, I can't even find the key keeper on the 1st level of the silver spire who has it. All other devices: rot, remorse, horror are there and not one at a time and the key holders are immediately found, but fear is not found. On the 6th torture. Maybe I just misunderstood something?