Stats for the Lord Ruler: 10 in everything. The End. :p
Try: Stats for the Lord Ruler: The End
I dunno. He's not literally undefeatable, just extremely powerful. I know Vin needed special mist-power to do it, but I think you could beat him with a Mistborn with access to Chromium (or a Leecher and a Coinshot/Lurcher) on your crew, so you could destroy his metals and use Steel and Iron to remove any metal vials he had.
Even if you somehow managed to defeat him, if I were running the campaign it would be over, due to the number of logistic headaches.
Of course, if you were in my campaign you probably wouldn't manage to kill him in the first place. I'd send Koloquisitors or something after you.