Genichiro Ashina I think the bastard's name is.
I think I'm going at him too soon, like I think the game expects me to go do other stuff first, but I can't resist the temptation to try anyways.
I've gotten to his lightning phase a few times but I can never stay alive more than a few seconds at that point.
I may go back to it yet. I do generally enjoy the challenge. But between him and the butterfly person boss, honestly more frustration with unfair bullshit than genuine enjoyment.