Thoughtful wore spectacles in the form of silver wires wound around his horns and down his forehead, suspending a circle of glass in front of each of his eyes. He had a deep voice, and was described as handsome.
The Jade Mountain Prophecy
When Darkstalker awakened, he arrived at the Jade Mountain library, where he asked Starflight for scrolls about what happened to his family. He briefly mentioned his sister, comparing her to Sunny, and the dragon she fell in love with. It can be assumed that this "glassblowing dragon with the spectacles" is Thoughtful.
While Darkstalker, Fathom, and Whiteout were playing Scales-and-squares at a festival, Thoughtful asked if anyone would like to do a scroll-stacking challenge with him. Listener, who was nearby, started to go with him. However, Clearsight then foresaw two futures: one, in which Thoughtful married Listener and they had a decently complacent life where Listener loved Thoughtful more than he loved her; and two, a future between Thoughtful and Whiteout that contained great pain, but also a wonderful love. Clearsight impulsively introduced Thoughtful to Whiteout, and Whiteout recognized Thoughtful as the creator of a glasswork piece named Cascade of Dreams. Thoughtful was surprised that Whiteout had understood the meaning of his piece, as no one had been able to decipher it before. Thoughtful and Whiteout then proceeded to play the scroll-stacking challenge together, much to the dismay of Listener.
A short time later, after Quickdeath failed to assassinate Darkstalker and was killed by Lionfish in defense, Thoughtful was the one who identified Quickdeath's body. He guarded the body with Whiteout while Darkstalker, Clearsight, and Fathom left to find out who had hired Quickdeath. Later on, when Darkstalker asked Whiteout about her "new admirer," she said that she liked Thoughtful and that he had given her a glass-blown shell necklace during the festival.
Thoughtful also appeared after Arctic's gruesome death, pushing through the crowd to comfort Whiteout. Thoughtful and Whiteout most likely left the Night Kingdom together and eventually got married to one another.
Whiteout and Thoughtful's future contained a great love, and according to Clearsight's visions, they were meant for one another. Whiteout described him as shining, and he was surprised and pleased when Whiteout recognized him as the artist of the Cascade of Dreams. He beamed when she accompanied him to participate in scroll tower.