The man known only as Rosa, Master Spy was born in the 19th Century on a ship to parents who had renounced their citizenship. Raised with allegiance to no country, Rosa was taken around the world and learned many languages as a child. When his parents were murdered in an uprising, Rosa escaped to the streets and learned to survive on his own. He was later forced into the British military to fight in Cremea but deserted and lived with circus folk, acquiring their skills. Eventually, he encountered the man who killed his parents, now king of a small Balkan nation. Rosa took revenge and realized his talents could be put to use for something valuable. From then on Rosa worked as a spy, accepting missions around the world provided the payment and moral issues suited him.
- 6 Appearances of Rosa, Master Spy (Earth-One)
- 1 Images featuring Rosa, Master Spy (Earth-One)
- Quotations by or about Rosa, Master Spy (Earth-One)
- Character Gallery: Rosa, Master Spy (Earth-One)