Selden is a normal human boy in his first appearances, but after interacting with Tintaglia, he begins to show changes associated with exposure to dragons. He first develops silver scaling across his brow and cheeks; eventually, he is scaled all over his body. Along with his sister, he is considered one of the first true Elderlings in recent times.
Selden accompanies his mother and sister when they flee to Trehaug after Bingtown is attacked in The Mad Ship. He becomes enamored with exploring the buried Elderling city. Malta convinces him to lead her into the city one night, and both are in the ruins when an earthquake occurs. Selden attempts to find Malta, but is unsuccessful, and is later found by Reyn Khuprus. Reyn brings Selden to the Crowned Rooster chamber, where they work together to open the domed ceiling and allow light to reach the last wizardwood log. They witness the birth of the dragon Tintaglia.
After freeing Tintaglia, Selden and Reyn struggle to escape from the Crowned Rooster Chamber until the dragon returns to aid them. Selden is one of the first to hear Tintaglia speaking, and he implores the other residents of Bingtown to help her.
Selden accompanies a Bingtown contingent that visits Buckkeep in an attempt to broker a trade agreement with the Six Duchies. He is intrigued by Tom Badgerlock when he meets him in a corridor, insisting that Tom seems important. Tom deflects Selden's questions, even after Selden is prompted by Tintaglia to ask if Tom dreams about dragons.
At the outset of the Rain Wild Chronicles, Selden has been missing for several years after leaving the Rain Wilds in an attempt to find more dragons. It is revealed that his travelling companions sold him into slavery. Selden spends time in a sideshow as an exotic "half-dragon" man.
Eventually, he is sold to the Duke of Chalced who believes that consuming Selden's flesh will cure him of his ailments just as a dragon's flesh would. The Duke drinks Selden's blood, which restores his health. The effect is only temporary, however, so the Duke keeps Selden alive to use as he sees fit. Selden is injured and weakened by the Duke's repeated drinking of his blood.
At the gates of death he is freed by the dragons' attack on the capital of Chalced. He is brought to Kelsingra to live as a true Elderling.