Trade and real estate. Both very sensible investments. That last idea, though...

Isidor turns to face him properly, a smile crawling back onto her face. "I thought about something similar." She twists, scanning around them for any nosy strangers and then inches a tiny bit closer, lowering her voice. "A kind of... 'arena' could be used to solve all kinds of disputes. It would be great entertainment, and people could try out their skills against opponents from all over the multiverse. You could host tournaments which guards and mercenaries could essentially use as advertising. The marketing potentials are limitless."