Jaghatai Khan rose from a foundling upon the plains of Chogoris to master of that whole world before the Emperor ever came for him, and the hard, swift wisdom of the steppe never left him. When at last he took command of the Fifth Legion he remade it in that image, teaching an entire brotherhood of Space Marines to wage war as the horse-tribes did, fast, subtle, and merciless in the pursuit.
Among his brother primarchs the Khan was something of an enigma, a warrior-poet who valued liberty above conquest and trusted deeds far more than titles. That independence defined his part in the Heresy. When Horus fell, Jaghatai neither rushed to Terra nor to the Warmaster, but withdrew to learn the truth for himself, refusing to be moved by anyone's assumption of his loyalty, and for a time the waiting galaxy did not know which way the Warhawk would ride.
His choice, when it came, was wholly his own: he judged the Emperor's dream worth preserving and threw the Fifth into the war on the side of Terra. The long, savage fighting retreat that followed, harrying the traitor advance across the void, marked the White Scars as one of the loyalist cause's most vital swords, and their primarch as a leader who could never be commanded, only convinced.