[Rumil]

Hi Urwen,

welcome to the Downs!

It's been a bit slow on Riddles recently, hasn't it. Hopefully we can get people going with a few guesses.

Ok, not sure this is the answer, many possibilities!

Three were we - The three elven ambassadors to the Valar
reduced to none - in Middle Earth
the first one
was slain alone - Finwe, slain by Morgoth
the second one
was slain for thing that shone - Elwe (Thingol), slain for the Nauglamir (Silmaril)
the third one
forever was gone. - Ingwe, stayed in Valinor, so forever gone from Middle Earth

So Finwe, Elwe, Ingwe, are my guesses