Contrary to popular belief, it is in fact, possible to go into Bismarck (Hard) and solo him.
There is some cussing in the video so beware. I spent food and potions on him and I had to get the 345 weapon and some better gear to even have the attempt to clear
https://www.youtube.com/watch?v=M5TdZuaxQoA
Guide to trying it yourself:
https://docs.google.com/document/d/1...it?usp=sharing