You do have some flexibility here as you go along. For example, you can kill Dancer of Boreal Valley fairly early in the game, allowing you access to Lothric Castle and its baddies.
But for the most part, unless you really want certain items found there, it’s best to proceed as follows:
Boss #1: Iudex Gundyr
Obviously you don’t have a choice here. As the first boss of the game, you have to beat Gundyr before you can even get to the Firelink Shrine.
He’s a good first boss, though. He’s not extremely easy, but he’s not bad once you figure out the best strategy for him.
If you’re having trouble with him, you can always re-roll a pyromancer. Fire melts him pretty quickly.
Boss #2: Vordt of Boreal Valley
This is where your path can split, as mentioned earlier. It’s better to go straight for Vordt though, as he’s much easier for a low-level character to take out than Dancer.
I think Vordt is easier than Iudex – you just have to be patient. If you have trouble with him, there are 2 NPCs you can summon: Lion Knight Albert and the Swordmaster (assuming you defeated him by Firelink Shrine.)
Boss #3: Curse-Rotted Greatwood
If you struggle with this dood, don’t worry- you can always come back to him (as I did.) He’s actually an optional boss, so you never have to defeat him. You do need to take him out if you want to convert boss souls into goodies, though.
As I said, I struggled with him the first few times I fought him, so I just skipped him and came back later. Definitely beat him the first try when I came back with my better equipment. Booyah!
Boss #4: Crystal Sage
This is where my Dark Souls III boss order diverged from how it should’ve gone. I walked right past the Sage and ended up in Farron Keep. By the time I came back for the Sage, I had leveled up so much that I destroyed him easily.
But even if you aren’t super-leveled, Crystal Sage isn’t too difficult. You can always summon Eygon if you need help, though.
Boss #5: Deacons of the Deep
…these guys are a joke. Once you figure out how to defeat them, it’s a breeze. This is kinda like the Royal Rat Vanguard fight of Dark Souls II in that regard.
I will say that if you’re a caster, you may struggle here just because the other deacons will tend to get in your way. Melee is the best way to go.
Boss #6: Stray Demon (Mini-boss)
This guy (high above Farron Keep) doesn’t have a fog gate and is completely optional. However, the area is definitely worth exploring and killing the demon gives you a soul used for items.
Even though there are no NPC summons available, you can probably find a player or two to help with the fight.
Boss #7: Abyss Watchers
One of the best fights in the game, defeating the Abyss Watchers opens a new fork in your Dark Souls III boss order.
If you struggle with them, just bring on an NPC summon… or three. Anri, Sirris and Horace are all available to take these guys out.
Also pay attention as the two watchers at the first half of the fight resurrect – one of them is the enemy of your enemy!
Boss #8: High Lord Wolnir
The first time I fought Wolnir, I died in about 3 seconds. I wasn’t expecting an insta-kill bad breath attack.
Wolnir isn’t bad, and his weakness is probably the easiest to spot in the game. Just prepare to do a lot of running around.
Boss #9: Old Demon King
Found in Smouldering Lake, the Old Demon King is a fun fight. I have 2 quick tips for ya, though. (DON’T LOOK IF YOU HATE SPOILERS):
Don’t kill him until after you beat the rest of the level. If you beat him right away, you can’t use the NPC summons to help you clear the area.
When he’s about to die, he has a last-ditch exploding attack that does a ton of damage. Be ready to dodge or block it – I can’t tell you how many times it took me out.
Boss #10: Yhorm the Giant
Another Spoiler Alert. Some people say this fight was way too easy, and it’s broken because of the Storm Ruler sword you can pick up during the fight.
Personally – I think it’s fine the way it is. Most people, unless they’ve read about it online, don’t even realize the sword is available for use against the giant. Most players probably die a few times to the giant before they go exploring mid-fight and find it.
But the sword does make this fight easier than the next, hence why I recommend you go after Yhorm first.
Boss #11: Pontiff Sulyvahn
This is one of the toughest fights in any Dark Souls III boss order, and solo players have a tough time with Pontiff. When he starts summoning a phantom, it can get tricky.
Personally I was able to beat him after 2-3 tries, but I also summon help for most boss fights.
Boss #12: Aldrich, Devourer of Gods
…I HATE Aldrich. It literally took me at least 20 tries – even with help – to defeat this joker.
Plus he’s creepy. Remember that he’s not the human-looking god, but actually the ooze eating the god.
It doesn’t help that just getting to his boss fog is a pain. But even once I got in, that arrow rain of death took me out over and over again before I realized you have to just keep running until he stops.
Boss #13: Dancer of the Boreal Valley
Some people say Dancer’s one of the hardest bosses in the game.
Personally, I didn’t think she was all that bad. And no, I didn’t cheese her with the column trick, either. I was just good at dodging her attacks, which takes a little patience.
As I mentioned earlier, you can actually defeat her much earlier in the game. But doing so with a weapon that is like +3 won’t be easy.
Boss #14: Dragonslayer Armor
I had a lot of trouble with this dood as well. He’s not nearly as bad as Aldrich, but it took me a number of tries to figure him out and just get patient enough to beat him.
If you decide to summon help, I recommend just summoning one phantom. If you summon 2 or 3, he just has way too many hit points and takes forever to bring down. Especially since you’ll likely end up summoning a player that sucks or have Sirris get killed before she can even heal herself.
Boss #15: Oceiros, the Consumed King
While definitely on the easier side of bosses, I didn’t really think Oceiros was a pushover. Maybe I just got too comfortable during my first fight or two with him, though. I ended up beating him on my third try.
…anyways, Oceiros is actually an optional boss. But if you want access to one of the coolest areas in the game, you gotta beat him.
Boss #16: Champion Gundyr
Remember your buddy Iudex Gundyr? Well, you get to fight him again… but he’s a bit harder.
He’s another optional boss, so you can completely skip him if you don’t want to visit the dark Firelink Shrine. But there’s cool stuff down there and his soul can be turned into an AWESOME ring, so he’s worth the fight.
Boss #17: Lothric, Younger Prince
Getting back into the mandatory Dark Souls III boss order, this fight gives you the feeling of being near the end of the game. Even though you’re not quite there yet, you can just tell the end is in sight – especially if you’ve paid attention to some of the items and lore that pops up during loading screens, as Prince Lothric is mentioned several times.
This was my favorite boss fight of the game, and many other players agree that the concept was just very cool.
Boss #18: Ancient Wyvern
This is another boss that, like Yhorm, has a “secret” key to defeat. Even though you can just stand toe-to-toe and hash it out, it’s probably tougher than just running the gauntlet to beat him “the right way.”
Boss #19: The Nameless King
The toughest boss in the game. What else can you expect from someone who is believed to be the firstborn son of Gwyn from Dark Souls?
While part of me wants to recommend that you fight him as the very last boss of the game, it just doesn’t conclude the game well. It doesn’t change the ending or anything, but there’s something to be said for defeating the next boss as the very last one.
Boss #20: The Soul of Cinder
As the final boss of the game, this fight is for all the marbles. It’s what finally establishes you as the next Lord of Cinder… if that’s what you choose to become.
Personally, I thought it was an anti-climactic ending to the game, but it is a neat fight.
And there you have it my friends! Again, you don’t have to follow this Dark Souls III boss order, but it is the most logical considering the difficulty of the bosses and the respective locations. Good luck!