A surprise Angelborn born to a minor Human house in Scil-Razan, Riyissan grew up to become the legendary hero of the Scycaen Imperium. At a young age, his keen military mind was noticed, and he was trained to become a Paladin of Thestus in Scil-Tellis. Possessing a mighty sword arm and anchored by holy purpose, Riyissan became one of the nation's mightiest warriors as a young adult, and moved to the capital Scil-Qallis to protect the the empire's nobility.
During this period, the Common League was expanding northward, and the empire found itself unable to respond as its vassal states competed and feuded. Believing he needed to act with singular intent, Riyissan took hold of Scyseti, the Epochal Artifact of the Scycae, and proved himself able to wield the "Sunreaver" at its full power. He convinced the Empire's vassal states to provide him with troops, and marched south, past the historical borderlands of the Wyrmhorn Reach into now-Common territory.
Through smart tactics and indelible might, Riyissan held off the Common army at the Battle Of Sylphglade, and left his indelible mark on the world when he sundered Scyseti's Cut, splitting the mountain in half. This act, along with his conquering of the Reach, left him as the most important figure in Scycaen history; he used his new status as a war hero to further consolidate power in Scil-Qallis.
The paladin become the first Imperator of a new "imperium", seeking to re-establish its grip on the north by reminding its vassals of Scyeti's power. He renamed the Wyrmhorn Reach to "Scyseti's Reach" and changed many of the old empire's laws, functionally turning the Imperium into a single-house monarchy under house Terrescel as he passed the Imperatorship to his daughter.
He only lead his empire for two decades, however, before old age consumed him. Despite having access to the Imperium's bast healers and mages, Riyissan simply lacked internal life force; many believed that his extended use of the Soulflare Sword had shaved off decades of his life.