Der-Suul is a skilled swordsman, powerful signeturge, and leader of the army of Trei'kur. He is the long-time rival of master swordsman Daril Camuze, who he has been trying to defeat for years.
War with Resulia
As the leader of the armies of Trei'kur, Der-Suul appears several times during the war with Resulia. He has a direct rivalry with Daril and therefore tries to clash with him often. While also a competent swordsman, Der-Suul is gifted with signets that allow him to unleash powerful fire-based attacks on his enemies.
Assault on Eastern Trei'kur
Despite being in charge of defending Trei'kur, Der-Suul could not withstand Resulia's counterattack against Eastern Trei'kur and lost the city to the enemy. However, because he is not one to be held back by honor or foul play, Der-Suul assaults Eastern Trei'kur the following night and directly attacks Daril.
The attack is thwarted, but before he makes his retreat, he launches a massive fireball directly at Relia. Believing that defending the weak is important above all else, Daril jumps in front of Relia, shielding her from the attack, but taking the full brunt of it himself. Weakened by the attack, Daril is powerless as he's surrounded and captured by Der-Suul's men.
Der-Suul takes Daril and Relia prisoner and holds them in the Trei'kur Slaughtery, an old military base once used to imprison and execute criminals. He sets a trap to capture Fideland his friends as they try to free Daril. The trap is unsuccessful in defeating Fidel, but Der-Suul again attacks Relia, but this time with his soldiers' Phase Guns. Again Daril blocks the attack, but he is unable to survive an onslaught of such advanced technology. Der-Suul laughs as he watches the great swordsman Daril succumb to his wounds.