Using a PoD after 1900, concot a reasonably plausible scenario where a single person has in personal union all royal titles that have (or had, at the time of your scenario) at least one pretender or holder in Europe. Bonus points if they can actively *use* that power (ie., the "no nukes" scenario). Double bonus points if they revive any "dead" titles they might hold (eg., King of Jerusalem). Triple bonus points and the title "Master Royal" if you can unite all the WORLD's royal titles on one head.