He was of Angrod's kin from the House of Finarfin.
Biography
For many years after the Nírnaeth Arnoediad, Arminas wandered with his companion Gelmir and sought Turgon and the kingdom of Gondolin unsuccessfully. Afterward, they lived with Círdan at the Havens of Sirion and were sent by him on an errand to Nargothrond bearing a warning from Ulmo of the impending doom of the hidden realm.
Before arriving there, they encountered Tuor at the Gate of the Noldor as he was about to leave Hithlum. When they arrived in Nargothrond, Arminas and Gelmir counseled Orodreth to shut the doors of his realm and remain a hidden folk. Arminas was mistrusted by Túrin, and the two argued over opposing views. Despite their warnings, Orodreth, under the influence of Túrin, did not listen to their advice. Arminas and Gelmir eventually departed south and reported what they were told to Círdan.
His fate is unknown.
Etymology
Arminas was likely Sindarin for "royal tower", from the prefix ar(a)-, meaning "royal", and minas, meaning "tower".