The Master of Death is a dangerous title; many would claim to hold a position greater than Death. Harry is pulled to Middle-earth by the Witch King of Angmar in an attempt to bring Morgoth back to Arda. A year later Angmar falls and Harry is freed. What will he do with the eternity granted to him? Story begins 1000 years before LotR. Eventual major canon divergence.

Having a deranged dark wizard after you is not too great. Having something you cannot quite explain after you in a strange world where the kindest fate is to find yourself on the wrong end of a sword makes that first thing seem like child's play. Geralt/Yennefer, Harry/? Rated M. Because there's no other way to write a Witcher story.