Tolkien's Elves were immortal beings with powers that far exceeded those of mortal Men, though these powers ranged from skill, art, and craft to the clearly magical. In "The Fellowship of the Ring", as the Nazgûl attempted to capture Frodo and the Ring from the Elf-Lord Glorfindel, Elrond (the Lord of Rivendell) commanded the river to rise, so as to sweep the Nazgûl away and drown their horses. Both Glorfindel, and Aragorn (a man, but with some Elvish blood) were able to tell the severity of Frodo's injury; Aragorn had powers of healing, especially against the Nazgûl's Black Breath.