Who designed the Death Star’s weakness in Rogue One?

The story behind the answer

Coerced into the Empire’s weapons program, Jyn Erso’s father secretly sabotaged the Death Star from within by building a deliberate vulnerability into its reactor design. In a holographic message to Jyn, he reveals the flaw and directs the Rebels to the plans labeled “Stardust,” allowing them to learn how to trigger a catastrophic chain reaction.

By contrast, Orson Krennic oversees the project’s construction, Jyn leads the effort to retrieve and broadcast the plans, and Cassian Andor commands the Scarif strike team. This revelation in Rogue One reframes the famous weakness exploited in A New Hope as an act of resistance from inside the Empire, giving narrative purpose to the Rebel victory that follows.