Intrepid

Intrepid was a Faction Paradox skulltrooper active after the fall of the Eleven-Day Empire. Although a child of the Great Houses, they were also half-human, and spent their lives fighting for their human side to remain dominant rather than their unearthly House heritage. (PROSE: Going Once, Going Twice, Hark! The Herald Angels Sing)

First incarnation
Auteur jeered that Intrepid, as a half-Homeworlder half-human hybrid, had been a "fleshy, pulsing runt in the loom's coils". A lithe, long-haired girl, Intrepid "aged in days rather than minutes", much faster than other Homeworlders. This half-human birth was seen as shameful, even if it was not as taboo as it had been in Auteur's day. This first incarnation had to renew unusually young because her body was fighting itself. (PROSE: Going Once, Going Twice)

Second incarnation
Intrepid's second incarnation, who still had not yet chosen this name, was a blue-eyed boy with long blond hair. He attended the Academy long enough to hear an assembly lecture by Cortalian of House Lineacrux, who had yet to be banished from the Homeworld, but was kicked out after only a couple semesters, not even having learned how to fly a Homeworld timeship yet, because hybrids had fallen out of fashion in "polite society". (PROSE: Going Once, Going Twice)

Third incarnation
At some point, the Academy dropout entered their third incarnation, a boy with "gunmetal eyes". His hair was now short and curly, his body "lithe, more fluid than solid". (PROSE: Going Once, Going Twice)

Joining Faction Paradox
Prior to taking the name "Intrepid", he consulted the loa and sifted through quantum strands to prepare for his first paradox, which would initiate him into the Faction. For the paradox, he stole some eggs from a splinter Coterie of posthumans and left them in a prehistoric swamp, thus retroactively establishing a well-known species of monstrous bog-serpents to have in fact been human-descendants all along. (PROSE: Daring Initiation)

While in the Faction's service, Intrepid travelled to the home planet of Kifah as it was being obliterated by a fleet of timeships] as part of the War in Heaven. Happening upon Kifah, he rescued him from certain death, offering him his hand and telling him to "Come with [him]". He subsequently helped Kifah through his own Faction Paradox initiation.

Working together, the two gradually fell in love — "gentle touches during rituals, a velvet glove on a burnt hand, hugs becoming longer, smiles becoming sweeter". Eventually, they shared their first kiss beneath the red skies of the Eleven-Day Empire, rendered slightly awkward by the fact that they were both wearing their Faction Paradox masks at the time. (PROSE: Going Once, Going Twice)

Living in the Shadow Spire
After the fall of the Eleven-Day Empire, Intrepid was among the Faction-members who hid out in the Shadow Spire, forming the Family of the Shadow Spire. Auteur and the Spirekeepers Mother and Father were excited to have a recruit with actual Great House heritage to work with; Mother and Father planned to lock him in the lantern room of the Spire with Auteur, hoping to use him to exploit his power to subvert the story of the Spire. Instead, Auteur gave Intrepid a number of lessons. However, all three were eventually disappointed when Intrepid's human half proved stronger. (PROSE: Going Once, Going Twice)

Intrepid remained in a romantic relationship with Kifah. At the Shadow Spire, they and Gustav watched Life's angels proclaim the end of the War in Heaven. (PROSE: Hark! The Herald Angels Sing)

Intrepid lost and found
Intrepid was one of the skulltroopers sent by the Spirekeepers to the Fields of Cratosi to recover the sarcophagus containing Apep, a powerful, sentient relic of the conflicts between the Sun Builders and the Osirian Court, whom Mother and Father hoped could be used to bring Faction Paradox back to the status of a major power in the War. When House Military got involved, however, a freak consequence of colliding alter-time states froze the entire Battle in time.

The Frozen Battle was later one of the items sold by Cortalian to the highest bidder at the First Auction in Heaven. Ironically, Apep's sarcophagus was another item in the auction, and Apep being recklessly released by Auteur created cracks in Time that unsealed the bubble of frozen time around the Battle, thus freeing Intrepid. Intrepid helped fight off Apep by very intentionally not looking at Apep, thus depriving him of the Observer Effect and lessening his grip on reality.

Intrepid, Kifah and Gustav then escaped the Auction moments before it, and the entire planet on which it had been organised, ceased to exist, by stealing Cortalian's timeship. Although Intrepid was skeptical of his ability to fly a timeship accurately, the three at least succeeded in taking off. (PROSE: Going Once, Going Twice)

Behind the scenes

 * Intrepid's parentage is not elaborated upon besides being half-human. One interpretation is that he is Leela and Andred's first child, conceived at the end of Lungbarrow and who was named for the Doctor; this would explain why Intrepid's birth name is never given in any of his appearances.