#also doylistically the first Kinslaying is the only one without named characters dying and I think that lessens the impact for readers

[lendmyboyfriendahand]

I think Argon died at Alqualonde.

When the second host of the Noldor reaches Beleriand, they have a lot of grief. Those who died on the Grinding Ice are tragic, but easier to talk about. They died in pain and fear, but they were trying only to fulfill a promise and to seek a new home. Mourning Elenwe can be done in public, with no discussion of fault or her having deserved it.

Those who died fighting their own kin are harder though, especially as Fingolfin doesn't want to start diplomacy with new neighbors by mentioning such an evil deed. He's also too proud though to accept sympathy under false pretenses, even for the death of his son. Fingolfin couldn't stand listening to Cirdan say platitudes about the sea and Ulmo's mercy to drowned sailors, no matter how well meaning. So for a while, he simply doesn't mention his youngest son at all. Those who knew Argon know how he died; those who never met him think Fingolfin only has two sons.

("Two sons at least thous hast to honour thy words" - Fingolfin's own voice echoes bitterly in his head.)

Argon was bold, and headstrong. He saw a battle and charged into it, right alongside his big brother. So tall, he made an easy target. Maybe it was his own foolishness that got him killed, but not malice. He didn't even know why they was fighting.

Slowly, rumors begin to spread among the Sindar. They say the second host fought a battle before the rising of the Sun, nearly on the edge of the Sea. The host took losses, but did not let it deter them. Fingolfin's own son died, surrounded by enemies, a victim of his own bravery.

The battle was against orcs because who else would elves be fighting?

(Maglor is a storyteller first and foremost. A public gift to Fingolfin would be full of symbolism and double meaning between the two kings, but he can grant his uncle space to mourn.)