"Nereid?"
"Yeah. They are supposed to be a nation of researchers, or so I've heard. Supposedly, the western seas have more ancient ruins than anywhere else, and the people who live there spend their time unlocking their secrets. It is the most likely place your brother would go."
Aside from Nereid, the only other place that has experience with ancient tech would be Oto. The ever-eccentric Empress Lana was as crazy about ancient culture as anyone in Nereid when it meant she would learn new ways to make a profit. Seiya and his mercenaries were at odds with the country of Oto, and there was also the fact that it wasn't the kind of place you could hide in either. Nereid, however, was another matter. It was a place that was isolated from the rest of the world. So, it would be the perfect place to hide as well as find someone willing to unlock the encryption cube carrying the blueprints for the Magiguns.