Captain Thunderbolt Vulpoon, indeed I am. But surely, this is against all the rules of skysailing!
~ Thunderbolt Vulpoon

Captain Thunderbolt Vulpoon is an antagonist in book 6 of The Edge Chronicles by Paul Stewart and Chris Riddel. He is a sky pirate captain, ruthless, amoral and cold, whose moral standards are nothing like seen before. He ignores Undertown's principalities of freedom and honour and enslaves many of its residents.

In the novel

When searching for Twig's crew, Twig and Cowlquape are at the Undertown docks, having already found three of the crew (Tarp the slaughterer, Sleet the quartermaster and Bogwitt the goblin) and Twig has been guided by a mysterious telepathic voice (which only he can hear, which is later revealed to be the voice of his lookout waif Woodfish) to get to a ship named the Skyraider leaving for the Deepwoods' Shryke Slave Market. The captain of the Skyraider is Thunderbolt Vulpoon. Cowlquape announces his name sounds horrible, because a vulpoon is a predatory bird with a long serrated beak, and what man would choose "thunderbolt" as his name because thunder is deadly and unpredictable. Twig says that only a vain and stupid captain would choose such a name because, in his experience, "Name wild, captain mild." They narrowly miss boarding the Skyraider and have to jump onto it, boarding just as it flies off. Cowlquape almost loses his grip and falls, but he is saved by Twig. Then the duo finally meet Thunderbolt Vulpoon, who announces himself in a pompous, fussy manner. He is a short, fat man with a waxed mustache, tricorn hat, and pirate coat. He is displeased by their arrival, and he threatens to get his servant and bodyguard, a trog named Grimlock, to throw the youths off ship. But Twig manages to impress him with his money, and Thunderbolt's eyes light up with the gold. Thunderbolt asks for fifteen each because they have "air of academics about you. From Sanctaphrax, no doubt, I'm sure you could manage fifteen!" Twig agrees only when Cowlquape's life is being threatened, and Thunderbolt welcomes them onboard, in a somewhat alarming change of character. He goes from being cruel and brutal to suddenly friendly and neat.

Thunderbolt Vulpoon examines the youths, shakes hands with Twig, and then does the same to Cowlquape, but Cowlquape screams as his palms have been scraped bloody by the ship rope. Thunderbolt promises to get Cowlquape repaired, and this is a little odd because many other captains would have thrown them off ship for boarding illegally.

Thunderbolt tells them that they are heading to the Slave Market, and the cargo, overheard when the ship sways in air pockets, are hammelhorns - so he says. Cowlquape doesn't believe him, and confides to Twig that he believes Thunderbolt Vulpoon has slaves on his ship. Twig doesn't believe this, because he says Undertown is free and that it is death to enslave anyone. Twig obviously forgot the trog in the pub a few days ago saying his ship had been carrying slaves and the trog came to drink to forget it. But Twig goes walking on deck and hears that they are bound for the Market.

He comes in in a panic and says he needs to talk to Cowlquape. But Grimlock the trog has just given them wine and in a talk with the trog they learn Thunderbolt Vulpoon is not kind, he starves his employees, and won't even let Grimlock have the cargo's clothes. Twig realizes the cargo is slaves, and when Grimlock says he's starved, Twig says he could do with new clothes instead.

Thunderbolt tells Grimlock to sort out the cargo, and Twig says to Cowlquape that Thunderbolt Vulpoon is the most evil pirate ever because of his slavery cargo. They are going to be handed to the Shryke roost-mother, Muleclaw. Certain death.

Twig orchestrates a mutiny, and him and Cowlquape ambush Vulpoon, surprising him because he believed them to have drunk the sleeping draught in the wine. Thunderbolt Vulpoon sent down a trog to deal with them but they fought the trog and knocked him out, but the trog said "I don't care what the captain says - you're going to get what's coming to you!" Leaving the trog unconscious, Thunderbolt is surprised by Twig and Cowlquape on the deck and Twig orders Thunderbolt to be trussed up in disgust. Twig commandeers the ship and flies it to the Market itself.

In the Market, a Shryke sister comes and bargains with Twig, who says Thunderbolt Vulpoon is a good specimen and Muleclaw would want him. Twig says Thunderbolt is from Sanctaphrax. After haggling, they arrange for the Shrykes to drag Thunderbolt Vulpoon off uttering muffled curses behind his gag.

In the Wig-Wig Arena, a brutal part of the Market, Twig, Cowlquape and Spooler the oakelf see Thunderbolt Vulpoon being led out of a cage, thrown into the Arena, and eaten alive by Wig-Wigs. Thunderbolt tries to protest feebly before his execution, and killed 29 Wig-Wigs before his own death.