Based on appearances, Black Knight Greatsword in DS2 looks like Black Knight Sword (which is a greatsword) in DS1, so they actually have the same strength.
I’ve played thru this masterpiece of a game like 30 times and this is one of my top 5 favorite weapons. Feels great to use and has respectable damage and stagger.
I thought the same, even as soon as I got it I said, it looks a lot like the force edge, this weapon will be the one I will use for the rest of the game hahahaha