Younger brother to the late Commandant Marcus Thalassinus Endrin, Flint apparently lived for days on the streets of Korvosa. He used his frightfully accurate senses to shoot down messenger birds, disrupting communications and keeping city leaders from learning about the threat of encroaching forces from Magnimar.

Flint was eventually spotted by Egan, who tricked the bird-killer into revealing himself to his exact double, Flint. The bird-killer led his twin (and a gang of angry nobles) on a chase through the Shingles. Although the other Lord Endrin tagged him multiple times with arrows, he was about to escape when Egan caught him with a reverse gravity spell. Onle of the other angry nobles, Lyyah, then stabbed the bird-killer through the heart.

The other Flint recovered some the stolen letters from the body, including a message from House Leroung promising support for his efforts. The body was then stored away.