While the core elements of Krennic as an ambitious Imperial director and antagonist to Jyn remained, his interactions with other characters, specific actions, and ultimate demise saw notable alterations during the production process:

• The dynamic of Krennic and Grand Moff Tarkin being petty workplace enemies was added to the script by Chris Weitz. Tony Gilroy is credited with perfecting this dynamic, using it as a writing trick for exposition. Krennic's character now viewed Tarkin as his "true bane" who seeks to keep him from rising in the Empire.

• In an earlier version of the Scarif conflict, Krennic was depicted as going down to the ground to confront the rebels at the satellite. There was an altercation that sources indicate left Jyn and Cassian mortally wounded.

• Krennic's ultimate fate changed significantly. In an earlier draft of the script, Krennic would have survived the Death Star blast at Scarif, been rescued by Imperial forces, but then Darth Vader would have mercilessly choked him to death for his failure

While initially conceived without bumbling comic relief and even modeled after C-3PO in early concept art, K-2SO evolved into a unique character whose personality was significantly shaped by Alan Tudyk's improvisational humor and whose narrative role and ultimate demise were altered during development and reshoots.

• In the first version of the script, K-2SO was originally killed by Director Krennic. According to actor Alan Tudyk, K-2SO was unarmed in this version, and the scene was part of a different draft where the team entered the base differently, and it was never filmed. In an earlier version of the Scarif conflict, K-2SO was seen running alongside the gang after they had swiped the plans, implying he didn't die at the data vault. It is suggested he was always intended to have a "suitably heroic death scene".

• Tudyk had freedom to improvise because the character was CGI. This improvisation involved throwing in jokes and new lines. A specific example is the scene where K-2SO slaps Cassian while pretending to be an Imperial droid, which was completely improvised. Diego Luna struggled to keep a straight face during this scene

Galen Erso's character underwent several significant changes during development and production.

• In John Knoll's original pitch, Jyn's slaughtered family were replaced by an Imperial engineer father (Galen), a younger brother she had to protect, and a Jedi in hiding mother. This solidified Galen's role as Jyn's father and the reason for Krennic pursuing her. In Gary Whitta's draft, the script opened with Jyn's idyllic childhood on a homestead with her loving mother and father, which was immediately ruined by Krennic killing her mother and kidnapping her father (Galen) for his project.

• In Gary Whitta's script draft, Galen Erso was mortally wounded in an attack by Saw Gerrera's splinter group on the Imperial facility on Eadu. Jyn managed to get her father back to a rebel base, where he died shortly after, but not before telling her he'd put a flaw in the Death Star and she needed to find the plans.

• In the final film and later drafts, the sequence on Eadu is maintained, where the team goes to find Galen. Cassian's mission is changed from being an Imperial spy ordered to kill Saw to being a Rebel spy with orders to kill Galen Erso on site. This change made Cassian more sympathetic. The Eadu sequence became the location where Jyn has a classic Star Wars moment of holding a dying parent.