The Emperor's Sword is a famed relic blade that was wielded by the Emperor of Mankind Himself during the Great Crusade and was eventually passed on to the resurrected Primarch Roboute Guilliman in 999.M41 by the Archmagos Dominus Belisarius Cawl during the Ultramar Campaign, just before he assumed the mantle of Lord Commander of the Imperium. The weapon had been kept safely in Cawl's possession for over 10,000 standard years, since the end of the Horus Heresy and Guilliman's first tenure as the Lord Commander.
Touched by the Emperor's own psychic might, this finely wrought, master-crafted blade is lit from hilt to tip with leaping flames. When it is swung, the burning blade draws pyrotechnic arcs through the air, able to slice through the stoutest of armour with ease.
- Eye of Terra (Anthology) edited by Laurie Golding
- Gathering Storm - Part Three - Rise of the Primarch (7th Edition), pp. 128-129