This would be for a sword.
It glows gently with an inner light when drawn, sufficient for elvish eyes to see in darkness, and its light seems to softly illuminate with Varda’s starlight that which is hidden. Its light does not warn of evil folk nearby, as so many of the fell swords of the elves do, rather its bearer sees more truly that which they gaze upon. It feels light to the hand that bears it, and rings clearly, as if wishing to sing, when it is drawn. Its blade bites deeply upon the servants of the Morgoth (and thus Sauron).
Relevant words seem to be:
Crist, cleaver
môr, darkness, dark, night
dúath, darkness, shadow
*dû, darkness
dûr, dark, gloomy, hellish
fuin, night, gloom, darkness
*daw, gloom
*dim, gloom, sadness
morn (i vorn), darkness
Relevant example usage:
orcrist, Orc-Cleaver.
I'm looking for a "gloomy" word that connotes evil, not just darkness. Dûr seems the best fit.
I see two possible patterns for the name:
dûrcrist or crist-i-dûr.
I'm leaning towards the first.