Finally finished all the DLC, except for the optional missions in the final one that unlock after you beat the game because they're pretty fucking absurd and I don't think I can do them without grinding. For some reason the 3rd DLC was really hard for me in general, maybe I was underleveled but fuck if I know, the mission levels don't mean anything in this game anyway.
I'm curious - what were your favorite/hardest/easiest bosses, guys? Don't count Derrick, because that's not really a boss, but a cutscene that lets you press some buttons in between, and all of those challenge "now try fighting two at the same time" bosses, which are designed to be the hardest fights in the game.
Here's mine:
Easiest:
Saika - holding block just makes you invulnerable in that fight. His melee sucks and his gun doesn't do enough stamina damage to ever break your block. Also it's pretty silly how you can block explosions from his bombs. I think the fight would have actually been challenging if you couldn't.
Giant Toad - for some reason every streamer/youtuber that I saw play this game struggled with this boss and then I noticed why - everyone tries to dodge that move where he jumps and slams his spear into the ground. It has a weird hitbox and hits you even if you think it won't. But if you block it you avoid all damage and have enough time to recover stamina while he recovers after the attack. Other than that I just found it easy to constantly get behind him, do a bunch of damage, block his downward thrust, repeat.
Vampire bitch - another boss everyone struggles with but I never died to in any of the encounters. Maybe it's because I've seen this boss before playing the game myself so I fought very cautiously because I knew that getting hit means death + I knew about the anti-paralysis items.
Otani (floating half-demon guy) - he has very few attack patters, only one dangerous move that can be blocked and in his powerup state his shockwave spam can be dodged easily by sprinting/dodging to the side.
Hardest (main game):
Shima - doesn't stagger, does a lot of damage and has good reach, has a lot of different moves (he fights like a fighting game character, even has multiple grab attacks, leg sweeps, etc.). And in his powerup state he has that fucking oneshot attack (the one when he lifts you into the air) that has the same almost instantaneous windup animation like his leg sweep + getting hit by even one attack can be lethal because he instantly applies the lightning debuff that slows you down. Hardest non-DLC boss for me.
Tachibana (2nd encounter) - with how early you fight him, I still was getting used to the combat. He's pretty fast and aggressive and some of his attacks oneshot. Very hard to beat while you're still a noob. I actually had an easier time in the optional mission where you fight him and Honda at the same time because I've learned the game pretty well by then.
Mitsunari - he's like a fighting game player that almost exclusively spams ranged attacks. Also has those annoying grabs that happen very fast and he uses them at range.
Hardest (DLC and overall):
Onmoraki - this is like a Dark Souls dragon boss on steroids and crack and one of two story bosses where I just went all out and used everything I had - living weapon, those special healing consumables, etc. I just wanted it to be over. He's fast, attacks pretty much all the fucking time and leaves barely any time to close in and attack him yourself. Also some of his moves always hit me when I was sure I was out of range. His wing attacks don't look that long but actually cover half the arena. His poison breath also looks shorter than it really is for some reason. Getting hit by anything twice is death and getting hit by most of his attacks applies that annoying wind debuff which reduced the damage to like 100 per hit, which barely moved his lifebar when I attacked. Also, since I was using a short weapon, hitting that horn on his head was very difficult. It was easy with the bow but then I ran out of arrows, so I had to wait for him to use his ground charge move, dodge in low stance, start running to him asap, switch to high stance while running (if I dodged the charge in high stance I couldn't make it in time) and perform a dash attack on his head. 2 out of 3 times it would fail, but occasionally I could hit his horn, which let me do some much-needed free damage.
Hideyori - the second story boss I used all my shit to beat. The main problem was that he's too fucking fat. Once I got his patterns down the first phase is easy - I just spammed that Ki shockwave move over and over, drained his stamina, performed an execution and then that sheathed sword lunge attack while he was down. Repeat that several times and phase 2 starts. Now draining stamina no longer worked, so since he doesn't stagger at all, all I could do is dodge or block his attack, do a few quick slashes and run away because if I didn't I would die. My attacks did so little damage to him that it took me 10-15 minutes to beat phase 2 in my successful attempt. Also annoying that his dual swords have 2 different elements, so if I took 1-2 hits from him I'd get afflicted with confusion and lightning, which usually lead to death because I couldn't dodge properly with this shit on me.
Maria - mostly because of the absurd damage her nearly instantaneous grab attack did to me. She did become much easier once I realized the shockwave she shoots in 2nd phase is physical and thus could be blocked at zero risk.
Mysterious Samurai a.k.a totally not Shima - my personal hardest boss from the main game is back, now with two guardian spirits and a new moveset (including a lightning strike that comes out of nowhere and hits me for 80% of my health when I'm sure I'm about to win). Still doesn't stagger, still kills me in 2 hits. I also really liked the circumstances surrounding this fight - he just shows up in a side mission with no warning, saying nothing and just attacks you. The game also never explicitly states that it's Shima (even though it's fucking obvious) and he uses Mitsunari's spirit and the same sad music that played when you fought Mitsunari plays in this fight. Dude launched a suicide attack to get revenge for his lord, feelsbadman. One of my favorite bosses in the game.
Special mention:
Hayabusa optional ninja boss that appears after you complete all the DLCs - I tried for a bit but I don't think I can beat him without grinding. He moves and attacks twice faster than me and kills me in two hits. Sometimes in one. And has around as much hp as Hideyori. This is an easter egg reference to Ninja Gaiden, right? Never played those games but I know that the protagonist is called Hayabusa. Well this boss certainly feels like he came from a different game, he's just so much faster than anything else you encounter.
Kelley's Clones - not really a boss, but fuck them. One of the most infuriating fights in the game.
Also the giant sea blob wins the most annoying boss trophy just because of how many times I fell in the water while trying to attack him. In general the giant monster bosses in Nioh sucked massive dick. The serpent final boss was pretty cool, but still worse than many human and medium-sized demon bosses.