The Doryu family wasn't always a noble house or a house at all. Early Doryu's show up in the history books as a merchant focused clan, that while prosperous did not enjoy much prestige. All this changed with Seth Doryu. The Goblin Wars raged and all children of Cormyr took up arms to defend it from extinction.
The Goblin War occurred from 1370 DR to 1371 DR. The war started when Nalavarauthatoryl, (a devil-dragon) massed an army of Orcs, Grodd goblins, the seven Ghazneths and other monsters to attack the country of Cormyr. Interestingly, although the war is refered to as the Goblin Wars, goblins only made up a fraction of the army, most of the fighting being done by the Orcs.
During this period, Seth only a young merchants son distinguished himself in the field of battle. Numerous times, he should have been cut down but luck kept him alive. Soon this was noticed and his fellow troops saw him as a good luck charm. Now grown confident and utilising his considerable charisma he was able to spur his fellow troops to fight and never give up. As a result he quickly rose up the ranks.
Alas, his luck seemed to run out as Nalavarauthatoryl himself landed upon the field. Casualties were immense and while King Azoun battled the fearsome devil Dragon he was struck, pinned to the ground and burnt under a torrent of dragon fire. Seth, covered in the blood of his comrades, burns crisscrossing his body did not hesitate. Raising his plain merchant forged sword he charged the fearsome Dragon knowing full well he would die. The creature turned and breathed fire upon him.
It is said that in that day the heavens smilled down upon Cormyr as a winged Valkyrie appeared behind Seth and cut the fire in half. His sword, now a gleaming torrent of holy flame, bit deep into the devil's body. It roared in pain but it wasn't enough to stop such a beast and it bit down on Seth. It was then the almost dead king pushed him out the way and was grabbed into the beasts mouth. Before it could kill him Seth stabbed at it again, distracting it for enough time that the King drew his vorpa blade and cut the dragon's head off.
His injuries proved too heavy to bear but before he died the King named Seth a hero of the realm and his family a noble house. Since that day his once brown hair had turned a brilliant white gold, his touch healed wounds and light gleamed around him.
Since those days House Doryu has grown even more and has become famous for its heroes, with swordplay skills without merit. Several of them showed similar powers as Seth and were considered blessed. Recently however such individuals are showing up more rarely. With fewer heroic feats their prestige has been waning and many young members have taken up wandering around the world trying to accomplish great deads.