That fight had me raging.The hardest boss in the entire game for me up to this point was that stupid gunner miniboss on the way to the Gun Fort. efffffff
I found the Gentipedes and Apes to be the easiest boss fights. Gentipedes were like beyond easy and took like barely a minute. Their rapid attacks were super easy to deflect perfectly and it just filled up their posture like nothing and then it was over.
Apes were tougher for sure, especially second time around, but their movesets were pretty simple so not a lot of attacks or stuff to watch out for so it was just deflect attacks(which I found super easy to do, get in a bunch of hits then run away from scream and repeat. Second Ape fight would have been cake if I had actually read the Finger Whistle description and didn't try to take on both at the same time, but still I beat it on my second attempt.
I'm at the end game right now and so far the hardest fights for me have been:
Owl>>>>>>>>>>>>>>>Genichiro>>>>>>>>>Snake Eyes Shirafuji>>>Seven Spears
These were the only fights I had to repeat more than like 5-6 times to beat and more like a 10-50.