Diulf was the King of the Furious Roar and the most powerful warrior in the tribe. He was a charismatic figure, holding great determination and leadership ability. As such, he was considered a great ruler, commanding much respect and loyalty from the tribe. He was once challenged for leadership by Megion and Diulf admitted that Megion was a worthy rival.
At first distrustful, Diulf attempted to fight against the Order of the One True Way but was won over by the leader of the Company's determination to assist the tribe, allowing him access to the Wraith Soul.
He was not a Starbearer in his original world, merely acting as an ally of the Starbearers there, but became one in this world after touching the Chronicle of the Furious Roar. After this, Diulf remembered his fight against the One King alongside Cougar and willingly joined the Company in their war against the Order.
A key member of the Company, Diulf led regiments in many vital battles during the war, including the liberation of Pharamond and the fall of Cynas. He got along especially well with Vaslof, the two often having passionate discussions.
Following the war, he continued to rule the Furious Roar, working on their prosperity and their relations with the other races. He would also father a child with Servillah, his loyal aide.
- Genso Suikoden Kiwami Encyclopedia, pages 781-2