Even though this was the first time Siena and Nalea met Rhode, he couldn't be more familiar with them. It could also be said that any players who experienced the second phase of the game knew who the twin dragons were.
In the game, they were the only BOSS-level figures who players were afraid to mess with and not even Rhode ever considered attacking the Country of Law. Even though the Country of Law was relatively sealed-off, had a neutral diplomatic stance, and never provoked players and foreign organizations, this didn't mean that players wouldn't consider attacking them. For instance, Erin was also like a mascot of the Country of Darkness where she wasn't involved with anything apart from acting cute for players and assigning missions to them. In the end, she was instantly slaughtered by players after Rhode killed the Dark Dragon and she lost the protection of the moon. This went to show that being harmless definitely wasn't the reason why players wouldn't kill someone.
