"Galactius armour" was created by White Wanderer as gift to mortal warriors, the symbol of maximum spiritual endurance, it is known to be the personification of Galactius itself- the Astral horse who rides through space and time. His inner glow is nothing but the never-ending energy regeneration of the univerve itself, the essence of everything that exists, has or will. Overlaid by mithril, the only metal that endures travelling between portals.
Name edit: Galactius = Galaxius