Hardest Bosses In the Dark Souls Series

Like many others, I too believe the Nameless King is the toughest SOB in the Souls series. Since my character can't parry, I had to utilize the most well-timed dodges to beat him. Even then, he got a few hits in before I took him down.
This guy... he's one of my favorite fights in the series but also the hardest. One time, I got super frustrated because I had him down to one hit left and then died. But then I summoned another player, and we took him down together.
Definitely the hardest, because it takes such a level of concentration and perfect timing just to avoid his attacks.
For me, all of the DS3 DLC bosses (apart from the Gravetender and Halflight) are very challenging. Midir just barely wins because of his health and absurd damage. You really do feel like you can die at any second. I feel like the Nameless King is much more predictable.
I haven't played the games because I don't dare to. However, there's a guy on YouTube who does lists on these games (including Bloodborne). He decided to rank the difficulty of the bosses in each game and graded them out of 10. I remember Midir receiving the highest ranking in the whole franchise (10.91/10), which says a lot.


Definitely one of the most aggressive bosses in the three games. He also has the highest health in the game.
In my opinion, this is the hardest boss in all the Souls games.
Smough and Ornstein have definitely earned their spot as one of the hardest boss fights in Dark Souls. I've lost countless souls to these guys. Out of all the bosses in the base game, this is the fight I have the most trouble with.
This fight is particularly difficult for me because I have a heavier build. I use Havel's armor (minus his helmet, which I substitute with the Mask of the Child), the Ring of Favor and Protection, and Havel's Ring. Without this setup, there's a 100% chance that I will get completely overwhelmed by Ornstein's speed.
Now, Smough isn't that hard for me to handle. I can move faster than him, and if I have Solaire to help me, he keeps Smough occupied while I work on killing Ornstein. I always kill Ornstein first because if I don't, the fight becomes almost impossible due to his speed. Super Smough is no problem because of his lack of speed. I'm able to land a few hits after one of his attacks that take a while to recover from.

The second "Aava" only appears when the first one's health is around 40%, so the developers weren't entirely deranged. Still, the period when you're facing both tigers can make even atheists pray.
The tigers are very fast, their attacks hit like a truck, and the windows for attacking are scarce because you can be hit by the other tiger. And the worst part? The bonfire is distant as hell from the arena, and the adrenaline of taking another shot at the boss is destroyed by the thought of completing the awful path to reach it. I was seriously reconsidering my policy in the Souls series of beating the boss solo, but then, out of the blue, I somehow killed him. Fire is their weakness, by the way.
One-hit AoEs, massive damage, massive range, enormous health. Enough said.
The best boss in the history of Dark Souls.
I beat him on my sixth try, but he is still hard. He's my favorite DS3 boss.
This boss can be pretty difficult. He deals fire, magic, and physical damage, and his combos can be quite punishing. However, if you can get his parry timing down, you can get him to half health with little to no struggle.
After that, though, he gets a bit harder. Not only can his clone hit you, but he also gains ranged magic attacks that hit pretty hard, so watch out for those.
From what I've heard, he's one of the hardest bosses in the game. Me? I didn't have too much trouble with him. That said, he has sporadic delays, heavy-hitting attacks, combos that can stun-lock you to death, and his AoEs are the worst. Plus, he has quite a health bar. Definitely a fantastic fight.
The Newcomers


Artorias is one of the hardest bosses to read. He can combo you easily, and he hits pretty hard.
When I took on the DLC, I was using a sorcerer build, and I found that the game is ridiculously easier (and, by consequence, less enjoyable) when you can Soul Spear everything from afar. So, this guy causes me some trouble, but not too much. On the other hand, I can foresee how insane Manus, Artorias, and Kalameet would be with melee builds. Mostly Manus - this guy should be something.
This dragon is a terror. Extremely difficult, nearly impossible when fighting him while he's flying.
God, this guy. High damage, high health, difficult-to-dodge attacks, etc.

This is the only boss I had to use a summon for in Dark Souls III. These guys were absolute hell, a lot harder than the Nameless King.

It's a shame that I missed this boss. From what I've heard, it's the best in Dark Souls II. I've also heard that it's one of the hardest.

There's one factor that prevents him from being ranked higher: parrying. While parrying is easier said than done, as his attacks are mostly hard to read, it becomes more manageable once you get the timings down.

This is one of the hardest main game bosses. He has high health and deals extreme damage. When he buffs, he damages you over time when you get close. This fight comes down to how much Estus you have before you, unfortunately, run out.
He barely takes any damage, and his fire attacks go through your shield with ease. There is a complicated way to skip him, which I use all the time. I hate this boss.
He isn't the hardest but can be a tough adversary if you're not careful. He hits really hard and can summon a player to assist him.