Crimson Desert: How to Get the Glowing Sword in the Ocean (and the Black Fang Sword)

30-second quick start (TL;DR)

• Target: the Forgotten Ocean Ruins pin in the South Sea, below the Rocky Reef label, at the end of a submerged ridge.
• Entrance: a cave mouth in the trench at about 225 m with a slight blue glow on top. The cave is long.
• The sword: inside the temple ruins at about 280 m, on the upper floor, not in the chest on the side path.
• Breath: bring a breathing device or accept that you will drown on the way out. The sword stays in your inventory either way.
• Black Fang Sword: southern tip of the Great Rocky Reef, next to the Sea of Silence. Take it off the giant walker’s back.
• Upgrades: the Lumen swords refine with Natural Pearls, which are rare. The Black Fang Sword uses ordinary materials up to Level 10.

What this guide helps you do

Two days into Charting the Unknown, the most upvoted post on the game’s subreddit was a photo of Kliff on a pier holding a sword made of light. Everyone asked where. This guide answers that, explains which of the game’s three light-blade finds you are actually looking at, covers the breathing gear that makes a 280 m dive survivable, and adds the other underwater weapon players found the same day, the Black Fang Sword.

Every location here comes from players who posted map screenshots and depth readings on launch weekend; Pearl Abyss has not published the spot. Where two reports disagree, we say so. If you have not opened the ocean yet, start with what the DLC unlocks and when, because diving itself needs nothing but the update.

Three light swords, one name: which is which

Players use “Lumen sword” and “lightsaber” for more than one item, which is why the Reddit threads contradict each other. Here is the split.

So if you want the two-hander, go clear the Garden. If you want the one you can pair with a shield, read on.

Gear for a 280 m dive

The basic diving suit from the update gets you to the reef. The trench is another matter: the cave is long, and the player who mapped it says plainly that you “need a backpack breather to make it in and out”. These are the options, cheapest first.

• Accept the drowning. You only need enough breath to reach the sword. Pick it up, and it stays in your inventory when the breath gauge empties. Ugly, but it works, and several players did exactly this.
• Pre-order diving set. If you have the Charter’s Diving Set or Light Diving Set, the helm and suit add about 120 breath each according to one report. Xbox players cannot claim it yet; see the add-ons guide.
• Propulsion-Type Breathing Device. A rare back-pack found in a treasure chest. It raises max breath by 60 and swim speed by 4%, and the wing attachment pushes you through the water. Players describe it as Oongka’s jetpack working underwater, for any hero.
• Enhanced Propulsion-Type Breathing Device. Crafted at a Carpentry workstation once you learn its blueprint: one Propulsion-Type Breathing Device, 50 Shiny Ore, 30 Malachite, 20 Manganese and 10 Hydrothermal Mineral Deposit. It lists +90 max breath and 6% swim speed. Players say the breath it actually gives is far longer than the card suggests, enough that some skip the diving suit entirely.
• Forsaken Oath Plate set. A four-piece epic set from underwater treasure chests, themed on a knight lost beneath the ocean. The helm alone gives +6 max breath at +0 and +30 at +10, Daze Immunity, spirit regeneration and a Swim Speed socket. Good armour for anyone planning to live down there.

Step-by-step: the glowing sword

Tick these off as you go. Your progress stays on this device.

1. 1Mark step 1 done

   Open the Great Ocean

   You need a boat or an underwater mount to reach the South Sea. Diving needs nothing else; the ocean itself opens with the update.

2. 2Mark step 2 done

   Sail south of the Rocky Reef label

   Open the map, find Rocky Reef in the South Sea, then look south-west for a long submerged ridge. The Forgotten Ocean Ruins pin sits where the ridge ends. Its card calls it “ruins of ancient times”.

3. 3Mark step 3 done

   Find the trench

   Dive at the pin. The sea floor falls away into a trench you cannot miss. The first player to post it set a marker just above the ruins icon and the trench ran right under it.

4. 4Mark step 4 done

   Spot the blue glow at 225 m

   In the trench wall is a cave mouth with a slight blue glow on top of it. That is the entrance. Check your depth readout: about 225 m.

5. 5Mark step 5 done

   Swim the cave

   It is long. If you brought a breathing device you will be fine. If not, do not stop for the loot on the way in.

6. 6Mark step 6 done

   Enter the temple ruins

   The cave opens into a sunken temple at about 280 m. There is loot on the lower floors and a side path to the right that ends at a chest. The chest is not the sword.

7. 7Mark step 7 done

   Climb to the top floor

   The sword is inside the ruins, on what one finder calls the third floor. Look for the glow. Pick it up.

8. 8Mark step 8 done

   Get out, or do not

   Swim back the way you came, or let the gauge empty. The sword stays with you after a drowning death.

The Black Fang Sword: the giant walker

While people were hunting the light sword, another diver found something stranger: a giant armoured figure walking slowly along the sea floor at the southern tip of the Great Rocky Reef, where the reef meets the Sea of Silence. It does not fight back. Punching it does nothing. On the back of its head is a sword you can simply take.

The item card in the first report was tagged Unequippable for the hero who found it. The game tags weapons that way when the character holding them cannot use that type, so check the sword on your other two heroes before assuming it is broken. The walker itself is a mystery: players have found a statue of the same figure elsewhere, and the running theory is that it is part of the ocean’s ancient defences. Treat it as scenery with a gift on its head.

Upgrading the light swords: Natural Pearls

Both Lumen swords refine with Natural Pearls, and that is the real grind. They are rare. What players have found so far:

• Large open clams on the sea floor sometimes hold one. Players found them around the coral reef colony and in an underwater temple directly below the serpent island where Aeserion lives.
• One player found a dispatch mission that pays out Natural Pearls, which is the only repeatable source anyone has posted.
• They sell for 190 silver, so a pearl in your inventory is easy to mis-sell. Lock it.
• Eating clams does not produce pearls. Someone checked.

The player who cleared the Garden first had not found the sword’s upgrade materials by the time they posted, which is why the two-hander sits at 25 attack in most screenshots. Expect the ocean sword to be the same story until the pearl farming is solved.

Troubleshooting and common mistakes

• Mistake: Looking for a ruins icon on the map and not finding one. Fix: Icons only draw at certain zoom levels. Zoom in on the ridge south-west of Rocky Reef until the Forgotten Ocean Ruins pin appears.
• Mistake: Opening the chest on the right-hand path and leaving. Fix: The sword is in the temple itself, upstairs. The first finder made this mistake and corrected it.
• Mistake: Diving the trench in the basic suit and turning back at half breath. Fix: Either bring a breathing device or commit. The sword survives your death.
• Mistake: Expecting the two-handed magenta sword. Fix: That one is the Garden of Trials reward. The ocean sword is one-handed and blue.
• Mistake: Attacking the giant walker. Fix: It ignores you. Swim to its head and take the Black Fang Sword.
• Mistake: Selling Natural Pearls as vendor trash. Fix: They are the Lumen refinement material. Keep every one.

FAQ