What Is The Most Powerful Sword That Dr. Doom Has Ever Wielded?

[JudicatorPrime]

I probably should have asked this in the Doom Appreciation thread, but this is likely a question that people who don't frequent that thread may know. (Mods, please move, if necessary.)

What is the most powerful sword that Dr. Doom has ever wielded in a comic book story arc? Feel free to list the names of any sword that was in VVD's possession at one time or another. I realize "most powerful" is a term that often invites interpretation, speculation and debate. Thanks!