I think you mean Don Plagueis the Wiseguy.
But the best is definitely when Michael Corleone and Hyman Roth fight to the death in a lava-filled casino. Fortunately, Roth loses the high ground and then doesn’t live to see the New Year.
Man that was so epic.
“It’s over Roth, I have the high ground!”
“You underestimate my offer!”
“You were the chosen one! You were supposed to close the deal not destroy it! Bring balance to the casinos, not leave them in darkness!”