Seven Kingdoms: Seowyn's Crossing
Valissor d’Argentius was a Dragonborn Paladin of Bahamut who lived about 350 years before the founding of the Seven Kingdoms. He was a Raysh of Azmartheon – a noble title that conveyed with it legal rights but no land, similar to a Banneret Knight. It’s known that in 378 PKR, he led an expedition to what is now called Wyvern Island and wiped out a colony there. Although most of the inhabitants of it seemed to have been Tishad, it’s clear from the remains found on the island that there were also a fair number of Yuan-Ti living among them. The eradication of the colony seems to have been with the blessing of both Bahamut and Tiamat and was carried out due to their “degenerate and profane ways”.