Sekiro's final boss is some bullshit, honestly.
If it wasn't obvious, it's bigtime spoiler territory from here on out.
First up is Genichiro, who I already bested in the early hours of Sekiro. He's not so bad, but a simple mistake or two can suck down a couple health gourds, and I'll need all my gourds to even get practice in with the next bit, which is just three more phases of a mad grandpa decked out with some of the quickest, deadliest moves in the game.
Die and you start with Genichiro again. No checkpoint, even though he's set up as a bluff. Beat him and Isshin the Sword Saint, aka Sword Grandpa, bursts out of his skin and says hello. It's a four phase boss fight and I hate it. I know. It was easy for you. Cool! I spent hours on some of Sekiro's bosses. I just don't have the time or impetus to prove I can do the sword thing well again. The blade and I get along just fine. I'm looking for a different kind of payoff from Sekiro at this point.
So after spending a few mornings trying to take the Sword Saint, Isshin Ashina, down, I figure, fuck it! Let's give that slowdown mod tool a try.