Maybe some of you played KotOR (Knights of the Old Republic, 2003). In one of the early quests there you fight in an arena and you are called "the mysterious stranger" during the fights. It's quite memorable in my opinion. And here in Reaper's March there is quest chain that involves fighting arenas as well and the announcer calls you the exact same name! It's very similar I think.
Of course it could be coincidence, but I thought maybe one of the devs was a fan and put this reference into ESO? Would be cool.
Georgion - Bosmer/Templar - PC/EU