I’m by no means the first person to talk about this but Gelmir’s death is one of the most disturbing scenes in The Silmarillion. In a book with no shortage of dark themes and storylines yet generally lacking graphic violence or descriptions of torture, the stark depiction of the mutilation of a helpless prisoner done solely to enrage and horrify the spectators is so jarring to read.
Gelmir is brought to the front lines from Angband already having lost his eyes or his vision during his captivity, such a disturbing detail in itself. We don’t need a detailed description of how this happened to create a deeply unpleasant picture; as disturbing as the more explicitly gruesome nature of the scene is Tolkien’s habit of leaving the worst up to the imagination. It creates a chilling combination
The herald who has come to the front boasts “we have many more such at home, but you must make haste if you would find them, for we shall deal with them all when we return even so.”
Then, in a shocking spectacle, his limbs are cut off and he is left to bleed out
Gelmir spends his last terrifying moments among his captors and tormentors while still in view of his people and his brother, who of course he cannot see. He dies in sight of what might have once been hope, with no comfort or mercy and barely anyone left alive to even mourn his brutal end.
And Gwindor soon will be trapped in the same caverns, experiencing the same horrors his brother did, giving new agony to his death. Perhaps Gwindor even meets prisoners who knew Gelmir
And this is no longer a new tragedy for the Noldor (and it never has for the elves who stayed in Beleriand). Many among their number has loved ones taken captive or who vanished and were beloved, hoped to be dead rather than the alternative. Gwindor might not be the only one there who has an imprisoned sibling, parent, or other loved one
And Gelmir himself is rarely remembered by name. His existence becomes synonymous with his capture and torture and horrific death and with his brother’s ensuing rage.