Citadel Gaurds

[Tar-Alcarin]

From what I have read there is not much to know about the Guards of the Citidel
But this was taken from the Enclyclopedia of Arda

Those honoured guards of Minas Tirith who were charged with protecting the Citadel, the highest and most important tier of the city. At the end of the Third Age, they were the only soldiers of the city to be liveried in the arms of Elendil himself - a white tree in blossom, surmounted by a silver crown and stars, all embroidered on a field of black. They also bore heirlooms of Gondor's ancient wealth, tall helmets wrought out of mithril, and bearing the carved wings of sea-birds. The numbers of these Guards is not known, but there seem to have been at least three companies (at least, one of their number - Beregond - is said in The Lord of the Rings to belong to the Third Company).