Serendipity Writes the Plot: Traviss named Darman after military writer Peter Darman. It was meant to be a placeholder name, but when it was accidentally released to the public, she ended up keeping it. That "Darman" could sound perfectly as a Mandalorian name was a coincidence.
Screwed by the Network: The book series was mostly disproved and had to be cancelled after the first Imperial Commando novel due to developments in the canon Star Wars: The Clone Wars.canonicity Despite Lucasfilm hiring Leland Chee to be the arbiter of Star Wars canon, George Lucas never considered any of what is now designated Star Wars Legends to be canon, even before the Disney takeover officially decanonized it.George Lucas had an entirely different vision of the Mandalorians than Karen Traviss, though Dave Filoni did borrow quite a bit of Traviss's worldbuilding for the Mandalorian story arcs in Clone Wars and Rebels (Lucas's vision of a pacifist, neutral Mandalore being represented by Satine Kryze's "New Mandalorians"). This led to Traviss rage quitting the EU (and posting a nasty rant on her blog comparing Jedi fans to Nazis).
There would have been a sequel to Imperial Commando: 501st, the sixth book in the series, but after Traviss exited from the franchise, it was obviously cancelled.
According to Word of God, Arla would've had her accept Bardan's offer to wipe her mind to forget the pain that Death Watch inflicted on her, but she also gets Identity Amnesia in the process.
After the fourth issue of the Evasive Action webcomic (and during the run of the Republic Commando books), illustrator Tom Hodges (who created Vhonte Tervho, the first female Mandalorian, for Traviss's Insider article about Mandalorians — Traviss would also mention her in True Colors) revealed he and Traviss would be collaborating on another webcomic, of which Hodges implied on theforce.net forums would be about Mandalorians. Though he indicated they were far enough in the writing process, nothing further came out of this, mysteriously.
Miscellaneous Trivia
Tycho from Penny Arcade is a big fan of the series and have met Karen Traviss in person. He's cited the Republic Commando series as being a defining point of the Star Wars expanded universe for him and is disappointed that it was retconned away by the current expanded universe.
the fourth issue of the Evasive Action webcomic (and during the run of the Republic Commando books), illustrator Tom Hodges (who created Vhonte Tervho, the first female Mandalorian, for Traviss's Insider article about Mandalorians — Traviss would also mention her in True Colors) revealed he and Traviss would be collaborating on another webcomic, of which Hodges implied on theforce.net forums would be about Mandalorians. Though he indicated they were far enough in the writing process, nothing further came out of this, mysteriously.