I'm glad to say I did manage to defeat 1st time Genishiro in the beginning, middle and ending of the game. The same can't be said about inner Genishiro. That guy was an absolute B I A T C H.
In this play-through I also faced Demon of Hatred. He may be harder than Ishin, since he forces the player to completely change their muscle memory of parrying for the win. I must say I kind of cheesed him, by using the phoenix umbrella for one of his move sets. It was the only boss I used prosthetic tools on.
It still is my favourite game.

Decent 9