The Legio Atarus (Firebrands) are a Loyalist Titan Legion of the Collegia Titanica, one of the military arms of the Adeptus Mechanicus. Founded by exiles from the Forge World of Phaeton, the Firebrands were considered by some to be a particularly fractious and ill-disposed Titan Legion before the outbreak of the Horus Heresy. Distrusted and looked down upon by many of their bretheren in the Ordo Titanicus, the Firebrands would go on to prove their mettle where other, more lauded names, would ignominiously fall.