There are still bits and pieces that Ginko doesn't understand here - all this talk of other worlds, alchemy and catalysts and tolls, is pretty clearly delving into territory that he isn't quite familiar with. But he's gradually getting some idea of what Ed is talking about.

He gives a small nod, and, for a moment, his gaze settles again on the stream of golden light flowing from Ed's shoulder.

"...So that's what you intend to use it for." His gaze flicks back to Ed's face, the surprise and curiosity from a moment ago settling back into his usual look of matter-of-fact neutrality. "Tell me, then. Do you have any theories as to what this 'catalyst' actually is?"