I don't dig it either. Paid full price for the game based on the overwhelmingly positive response here. Spent hours getting destroyed by the third boss. Bitch would one-shot me and then it took like 30 minutes just to get back to her. Fuck that noise. I'll probably never boot the game up again. Some of y'all are either epic gamers or extreme masochists.
In the path leading down to the open area with the little side path that leads up to the boss, there is a ledge there you can drop down to. One of those enemies that spawn from the cloud is there, kill that and you see a shrine right behind it. The run to her is 30 seconds from that, not 30 minutes. There is no boss in Nioh that is further than 1 minute from a shrine either from a new shrine or a shortcut to an old one. Also stack paralysis resist, but mainly if you switch to middle to low stance in basically any weapon on her, you can skip around any time she flies up into the air. I had a really hard time with her using an axe, but she was trivial with swords. Just chain dashing around and hitting her every now and then. Takes longer since you do less damage, but she has a real hard time hitting you and has a very repetitive moveset.
Up in air, shoots at you, dodge around in a circle. She flies down and misses, dodge into her, hit twice. Dodge back. She starts doing her spin kicks, dodge back 3-4x, dodge in hit twice, dodge back. Do that twice and she'll probably fly up again. Rinse repeat.
Not done the higher difficulties, but I found Nioh much easier than Dark Souls. Example, the K... something weapon that you spin trivializes any humanoid mob with its Scorpion get over here move. You can take on any level summon with it just using that move, hitting and dodging back and doing the move again once they stand up. Also works for most of the challenges since they usually have human enemies.