Emperor Rael knew that there was a good chance that the Republic of Gorteau and the Sekigahara Confederate would consider Rui as a strong point of investigation to obtain the means of mass breakthrough.
Not because they had some reason to suspect that he himself was responsible for them
No.
But because of how powerful his position within the Kandrian Empire was.
Not only was he a prince of the Royal Family, but he was also a member of the Master Council. In addition, prior to Emperor Rael's return, he was undoubtedly the most powerful man in the Kandrian Empire.
If there was anybody who would know, it was surely the Void Prince.
"So you're saying I need to be careful when I visit the Panamic Martial Federation?" Rui asked, raising an eyebrow.