Prince Smolder is a male SandWing, the sole SandWing prince and the only living brother of the three sisters, Burn, Blister, and Blaze. Similar in appearance to Blister, he has pale yellow scales, a narrow face, dark-lidded eyes and black diamond patterns on his scales. He keeps keys, pouches, and bells around his neck. Sunny described his voice as sardonic and fairly normal, unlike Blister's unsettling tone. She said that she could not tell whether he was joking or not sometimes.
He fought on Burn's side in the great war, yet Burn seems to dislike him, possibly because he resembles Blister in his appearance, or because of the rivalry between him and her mother. He isn't the only brother of the SandWing sisters, but the other two "made the wrong dragons mad", probably his sisters, and were presumably killed. He loved Palm but Oasis did something to her, and Palm was never heard of again.
In The Hidden Kingdom, Blaze says her brother fell in love with a dragon her mother would never agree with, and she broke his heart. This was Smolder, and his girlfriend was Palm, who was never seen again.
In the epilogue of The Dark Secret, he is seen in Burn's stronghold speaking to Burn about the Dragonets of Destiny. He and Burn plot to kill all of the dragonets. He also stated about a prisoner that was revealed to be Queen Scarlet. He also stated that he wasn't used to calling Burn "Your Majesty".
In The Brightest Night, Smolder is running Burn's stronghold while Burn is away, looking "for a certain quintet of dragonets." He leads Sunny to the tower where Burn stores her collection and "special" prisoners, such as Queen Scarlet. He introduces Sunny to his pet scavenger, Flower. He shows Sunny that Flower is trained to come when she hears Smolder ring a bell among other things about her. After this, he proceeds to lead her to her cell in the tower. After seeing how miserable Sunny was he decided that he'd take her out at midday for a walk every day. He is actually quite a nice dragon, even though it's Sunny thinking. He also explains to Sunny the mystery of the missing SandWing treasure, showing her the doors to the previous treasure holds and revealing to her a clue about the Eye of Onyx, telling her if any of the other SandWing sisters had the treasure, they'd be queen already.
He later unchains Sunny and orders Camel to watch her as he organizes troops to defend the stronghold. Thorn and the Outclaws were attacking the stronghold, and Smolder was successfully fending them off. Sunny begs Peril to stop the fight to save her mother, and she does so.
Smolder then leads Thorn, Sunny, and Peril to Burn's collection, on Thorn's orders to see the dead, stuffed NightWing that Burn owns.
Later, Smolder leads Thorn and Sunny into the library and locks them in there, claiming that Burn would kill him if she found out that he let them leave. Thorn and Sunny escape and part ways.
At the choosing of the SandWing queen, Smolder is present and hands Burn, her sister, Blister's gift. The gift happens to be two dragonbite vipers, one of which kills Burn, the other nearly kills Clay. Blister and Blaze fight until Sunny finds the Eye of Onyx and gives it to Thorn.
Smolder apologizes to Thorn, and Thorn claims that it would be hard to forgive him.
Although he does not formally appear in Winter Turning, there is a letter from him addressed to Vermilion on how to look after a scavenger, which is also in the special edition of The Brightest Night.
Smolder approaches Six-Claws while he is digging up a shrub to inform him that Blister and Burn are up to something. He hoped Six-Claws could come up with a way to fix it, for he doesn't want to get involved. When Six-Claws thinks that Blaze could be in trouble, Smolder refuses to help and flees back toward the palace. Later, he is seen sobbing over Palm's disappearance, unable to be comforted. As he and his brothers discover the dead Queen Oasis, his eyes glimmer with satisfaction at her death, for she had taken away Palm.
"I have heard that before, there was someone who used to tease me about it. She told me she was going to assume everything I said was a joke, since that would simplify things. You can do that too, if you like." -To Sunny
"I think I should put you in the weirdling collection. It's as safe as the dungeon, but more comfortable. Also more psychologically destabilizing."
"The idea that you might actually belong somewhere like that, it's driven a few dragons insane."
"There used to be three of us, but the other two made the wrong dragons mad." -Smolder, talking to Sunny about his brothers
"You can live for now, but I'd appreciate it if you made you escape attempts as feeble and ineffective as possible."