The Devastation Ensemble is Hades' full body armour suit.
It is covered from head to toe in weaponry, and is described by Viridi as having likeness to a 'Rainbow Apocalypse'. On it are many guns that shoots lasers at Pit, and it also has face guns that are, of course, shaped like Hades' face, so the last thing Pit sees is Hades' 'Godly visage'.
It is presumably destroyed when Hades is destroyed, due to there being nothing left of him. If Hades ressurects himself there is a large chance he would remake the Devastation Ensemble, so it's chance of returning is high.