I love this thread!
In real life, I am a Mary. And I used to play Magic: The Gathering and participate in a community for same in my local area. For a long time, I would append "...of DOOM!" to many declarations - while playing the game, while hanging out, pretty much whenever.
At one point, someone was writing a thread about people going to a tournament, or something, and mentioned me by name, but called me "Mary...of DOOM!" And here I am...something like fourteen years later? I love it. I pick it as a username EVERYWHERE.