An oratorio is a large-scale piece of music for choir, orchestra and vocal soloists, which tells a story without staging or costumes. Most oratorios are based on stories from the Bible, a source that Handel's English audiences knew well.
Enthir is a Bosmer sorcerer and merchant found at the College of Winterhold, and has connections to the Thieves Guild in Skyrim.
I found one on Skyrim Nexus that seems to work. There was nothing in a Sweetfx search on the Oblivion Nexus. I Googled to find the one I am trying now. Now to find something like Imaginator for Oblivion.