In Dark Souls III, Smouldering Lake doesn't need to be that difficult... unless you're me. These tips will help you own this area like a baws.
In Dark Souls III, Smouldering Lake kicked my tail more than it should have. It's not a very big area, but I made some big mistakes going through it. Hopefully I can help you avoid the same fate.
Here's a guide to some of the things you should probably know before entering Smouldering Lake.
Note: There will be some minor spoilers here, so if that's not your thing, stop reading now.
...Still here? Okay, good. Here we go:
As soon as you step foot into the water, you'll start getting pummeled by giant ballista bolts. Even though you can dodge them and hide behind the giant pillars, they make navigating the area a pain in the rear.
Instead of even trying, it's better to wait until you get further into the area and can shut the thing off. It will take you a while to get up there, but it's worth it. Those Large Titanite Shards and giant worm in the lake can wait.
But before you turn off the ballista...
When you're standing in the lake and looking at the giant sandworm, turn about 45 degrees to the right. There's a Speckled Stoneplate Ring on the far side of the lake. The problem is it's behind a destructible brick wall, and you need to get the ballista to destroy the wall for you. Just stand next to the wall and the ballista will destroy it -- just try to dodge out of the way when it does (or if you're a beast, take the hit!).
The ring isn't bad, as it gives you resistance to magic, fire, lightning, and dark.
When a giant creature jumps in your way in Dark Souls III, it's tempting to just lay into it. But as long as that ballista is trying to turn you into shish-kabob, it's not worth the effort.
Instead, just run past the worm. Once you get onto the dry land, turn right and go up the stairs. As you turn a corner and go back down stairs into a cave, you find the next bonfire. This is the best bonfire for both attacking the Old Demon King and going through the rest of the level.
But while it's tempting to go straight for the boss...
I'm not sure if Dark Souls is trying to troll you here or give you a bit of a break, but they make it tempting to go straight for the Smouldering Lake boss.
There are 2 main reasons for this:
So even though that fog gate looks interesting, just ignore the big guy for a while. Especially if you want to see Knight Slayer Tsorig lay into a few demons with his sweet greatsword.
Oh, and speaking of Tsorig...
The interesting thing about this joker is that you can summon him at the Demon Ruins bonfire.
But you actually have to fight him later in the Ruins. There's a part where you come around a corner and start going down a narrow stairway, then see this behemoth in Black Iron armor and a giant greatsword running at you.
Fortunately, Knight Slayer Tsorig doesn't really like knights. Hence, his name. So I watched the two duke it out, and gave a little toast to the Black Knight for saving me.
Tsorig won the fight, but had just a sliver of health left, so one swing of my Longsword ended his (short) reign of terror.
To do the same thing, lure Tsorig up the stairs and down the corridor you came from. When you look left, you'll see a giant staircase. Go up there, and across the bridge is the Black Knight.
It may be a cheap way to kill the man, the myth, the legend known as Knight Slayer Tsorig, but I just wanted to see if he could actually live up to his name.
So there you have it. Good luck in Dark Souls III's Smouldering Lake -- hopefully you don't die nearly as many times as I did there!