21 of 30
21. Okatsu: Okatsu can be tough and fairly frustrating until you learn her patterns. For the first part of the fight, it's simply a case of dodging and punishing when she finishes her combos. Then, once she summons her guardian spirit, be aware that her combos extend and she'll add an additional wall jump kick to the end of her attack chain. Make sure to block or dodge this, then punish. Okatsu is fairly easy to trap in a corner of the room, though, so make sure your guardian spirit gauge is full before the fight and you can shave a huge amount of her health off by swinging away at her when she's near a corner.
22 of 30
22. Ogress: Ogress is slow, and has some huge windows of opportunity for you to deal out punishment, but don't underestimate her. Her attacks are hugely powerful, especially her repeated claw-slashing that can catch you in a stunlock and take you out the fight if you're not careful. There's a temptation to just go all out on Ogress given how large and lumbering she is, but watch for her suddenly lashing out. When she begins to grow lilies, be prepared to purify the area with precision timing as her Yokai realm corruption can end up covering the entire space.
23 of 30
23. Honda Tadakatsu: The first time you fight Honda, you don't need to fight him at all; simply run around and smash the three purple crystals in the arena. He's slow and gives you plenty of time to do this. You can even destroy one of the crystals before the fight begins, by shooting a barrel from outside of the arena. The second time you fight him, he's a bit tougher; make sure to dodge away from him when he swings his axe. He'll also heal the majority of damage you do to him when you get him down to about 50% health; unless you're OP there's nothing you can do about this other than chipping away at him until his healing power subsides.
Summon: No, then N/A
24 of 30
24. Ishida Mitsunari: Mitsunari has an absolutely huge health pool and some very heavy attacks, but the window of opportunity to punish him is rather large. This fight's simply a case of chipping away at him, keeping on your toes when he attacks, dodging around him and slashing him from behind. Make sure you've got the maximum amount of elixirs as it's a long fight to have to redo, but by the time you reach Mitsunari your skills at dodging and blocking should be such that he doesn't present much of an issue.
25 of 30
25. The Dark Samurai: Another fairly simple duel fight, but one that's easy to lose if you're not paying attention. The Dark Samurai uses a hefty axe, so his attacks do a lot of damage, and they have a relatively large area of effect, but he's slow and easy to punish. Play it quick and fast, weaving around his attacks, then go to town on his back for extra damage. His guardian spirit is imbued with lightning, so lightning charms can be helpful here to try and minimize some of the massive damage this guy does.
26 of 30
26. Shima Sakon: Sakon can be a bit of a challenge, thanks to his speed, range and power. Try to avoid tackling him head-on as he can flip you with his spear, and when he summons his guardian spirit it's better to keep your distance and wait till it runs out before dealing damage, unless you're very confident in the attack window you have. Ki damage is key here to stop him using some of his more devastating moves, so using a weapon with Ki damage can aid the fight tremendously.
27 of 30
27. Umi-bozu: Umi-bozu can be a bit of a nightmare because it has a one-hit kill blast. It's very important to light all the torches in the level, then frequently imbue your weapon with fire from the cairns in the boss arena. For the first half of the fight, keep your distance and prepare to quickly dodge left or right when you see it charging up to spit. If it brings one arm out, then watch the direction of the attack, quickly dodge it then attack its glowing hand. If it brings both arms out then run towards Umi-bozu; the arms will always land in the same place, away from its body. If you feel daring, rush in and attack its head. When Umi-bozu shrinks and appears in the middle of the arena, simply attack it whenever you have an opening. You're safe from the one-hit kill attack from this point on. Just beware of the smaller henchblobs in the arena.
28 of 30
28. Hino-enma: The dreaded Hino-enma is Nioh's first real difficulty spike, and has been the foil of many new players. The windows in which you can punish her are extremely small, and her attacks can be devastating. Blocking her ground attacks works best, since dodging them is almost impossible and moves you too far away to get some hits in. Be sure to learn her tells for her paralysis attacks too, which take the form of projectile hits. They're easy to dodge if you can recognize them. As soon as she attacks, get a couple of hits in then get away. If she grabs you, she'll heal. Really, though, this fight's designed for co-op and is MUCH easier with another player.
Summon: Yes, this is the most co-op centric boss in the game
29 of 30
29. Tachibana Muneshiga/Honda Tadakatsu: This is where things get really, really tough. Both of these guys pose a challenge by themselves, but together they're ridiculously hard. Simply trying to keep an eye on what both of them are doing is a mammoth task by itself. Tadakatsu can throw rocks, and Muneshiga can do a long-range charge attack, so they can clear the distance of the arena with no trouble. The best bet is to focus on taking Muneshiga out first, since he's quicker. The more healing items and buffs you can use the better. You also get a bit of a window to shoot one of them before the fight starts, so getting in an early headshot with the hand cannon can help.
Summon: N/A. Weep.
30 of 30
30. Yuki-onna and Oda Nobunaga: Hands down the most difficult fight in the game, taking on Yuki-onna and Nobunaga together is a hugely daunting prospect. Yuki-onna dishes out her area of effect and projectile attacks while Nobunaga gets in close and just decimates you. Don't be afraid to leave this fight and level up a bit more in Way of the Strong difficulty before you come back here and finish them off. Focus on Nobunaga first and try and lure him away from Yuki-onna, but no matter what tactics you use here, it's going to be one ridiculously hard fight.
Summon: N/A. Double weep.