Rodan’s origin story could excuse his losses to Ghidorah and Mothra in Godzilla: King of the Monsters. In the movie, Rodan failed to take down either of the Titans. As things stand, the King of the Skies is still winless in the MonsterVerse.
Prior to the movie’s release, King of the Monsters director Mothra, who incapacitated him with his stinger.
Rodan losing twice obviously wasn’t a good look for him, but it could be that there was a good reason for his inability to get a win. Dougherty previously confirmed that Rodan’s parents nested in the Isla da Mara volcano [via Twitter]. According to him, the Titan was born there. A theory that builds off Dougherty’s comment postulates that Rodan was extremely inexperienced during the timeframe of the movie and that King of the Monsters was Rodan’s first time in the outside world [via much more powerful Ghidorah) is understandable.
If Rodan had never fought another monster before, it makes sense that he would lose to a seasoned opponent like Ghidorah, or even Mothra, who has lived an untold number of lives in the MonsterVerse’s timeline. If Rodan had more experience, it could be that he would’ve defeated Mothra. He likely still would have fallen to Ghidorah regardless, but potentially could have put up a better fight.
Rodan having this origin in Godzilla: King of the Monsters would shed some light on certain aspects of his species’ history in the MonsterVerse. A mural in Godzilla’s underwater home showed him fighting alongside Mothra and Godzilla against Ghidorah, but if he never left the volcano, this creature may have been one of his parents or possibly an ancestor. That means that the Rodan featured in the movie could have had a fresh slate and no memories of any previous battle with Monster Zero.