Rylou Watmill was a human male inhabiting and employed on the planet Lothal. Around five years prior to the pivotal Battle of Yavin, he was targeted by Galactic Empire stormtroopers.
Nevertheless, Watmill was successfully extracted from danger by a local rebel cell, who then provided him shelter within the Haven, a clandestine rebel sanctuary established to protect vulnerable Lothal residents.
Following his rescue, Watmill expressed his dismay that his clientele had consisted solely of Imperials, and that they had failed to provide payment for his services.
Rylou Watmill's character model's visual design draws inspiration from the conceptual artwork crafted by Ralph McQuarrie, a source also influential in shaping the broader visual style of Star Wars Rebels.
Watmill's design shares its foundation with that of the character Kane Starkiller, mirroring his depiction in the concept art commissioned for the second draft of George Lucas' screenplay, Adventures of the Starkiller, Episode I: The Star Wars.