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Sea of Stars

Sea Slug Boss Guide: Sealed Docarri Ruins - Sea of Stars

Jarrod Garripoli

One of the endgame side quests in Sea of Stars involves the Sunken Docarri Ruins. You will have to visit three ruins that contain puzzles, and upon solving each of them, retrieve a Seal Fragment. There is also a fourth set of ruins, but this one is locked by a door that has three indentations for objects on it. Once you place the Seal Fragments in the door and go through it, you will be fighting a boss. This page will detail the strategy and information on the Sea Slug boss fight.

The Sea Slug is waiting for you at the end of the Sunken Docarri Ruins side quest.

Where to Find the Sealed Docarri Ruins in Sea of Stars

Before you can do anything, you will need to have the ability to fly, which is done right before you go to the final story dungeon. Once you’re at that point, you will be able to start the Docarri Ruins side quest, so visit the How to Find the Sunken Docarri Ruins page for more info. You will also need to have completed all three of the Sunken Docarri Ruins first, so follow the links below for all the solutions to the puzzles:

(1 of 3) The light pillar will be just west of Mirth.

With all of the Seal Fragments in your inventory, head to Settlers Island (the one with Mirth) and look to the west of that island to spot the light pillar. Shine it on the rune, then follow the trail over to the eastern side of Settlers Island for the whirlpool. Head inside and place all three Seal Fragments in the door, then go through it to face the Sea Slug boss.

How to Beat the Sea Slug in Sea of Stars

The Sea Slug is basically a reskin of the very first boss you face in the game, the Bosslug. It will have all of the same moves as it, but they will have different properties, so expect a good challenge from this fight. You should be coming into this battle with a good number of food items, as well as all of your characters at full health. You will also want to be careful with crossing the threshold for the Rock Drop, as this doesn’t actually take up the boss’ turn, so it can follow up and KO some characters.

All Sea Slug’s Attacks in Sea of Stars

For now, let’s take a look at all of the attacks that Sea Slug can use in this boss battle.

  • Sludge Spit: This is pretty much its basic attack. The Sea Slug will spit some purple sludge at one of your characters. For this battle, the purple sludge seems to do 50% of your current HP as damage, if it’s unblocked. If you time a block, then it will deal lesser damage. At some point, it will start doing two purple balls of sludge each time it attacks, which deals even more damage than the normal version. You will need to time blocks for both hits, in this case.

(1 of 3) The Sludge Spit seems to deal 50% of your current HP, if unblocked.

  • Rock Drop: Sea Slug will thrash around the arena, causing two boulders to drop from the ceiling, one on each character. This attack is separate from its other two attacks, as it seems to do this at certain HP thresholds. All characters will be hit and their HP reduced to 1, even if you perform a Timed Block, as well as have a Lunar Shield active. Note that this attack doesn’t take up the boss’ turn, so it’s possible it can follow up this “attack” with its normal one.

  • Acid Bug Bombs: This is the move that will occur whenever you see the locks appear on this boss. Thankfully, it’s not a move that does damage, but the Sea Slug will summon some little purple bugs into the battle. The number of Locks left is the number of Bossbugs it will summon, up to a maximum of four of them. These are independent from the boss and will just sacrifice themselves to deal some damage to a single character. Unlike the Bosslug battle, the Bossbugs here have very high defense, so despite their low HP, they are annoyingly resilient.

Strategy for the Sea Slug Boss in Sea of Stars

The Sea Slug is a tough encounter, as it will have Lock combinations that can be difficult to break, and the whole Rock Drop attack is just annoying. In fact, you will want to be extremely careful with Rock Drop, as it is independent of the other normal attacks, meaning it is triggered at certain points during the fight (likely HP thresholds). The rocks will leave all of your characters with 1 HP, no matter if you have Lunar Shield active or time a block. If the boss has an attack coming up after this, then it will attack again (same goes for the Bossbugs), and one or more characters will get KO’ed.

(1 of 3) The Rock Drop attack can leave your characters open to getting easily KO’ed.

Of course, you don’t know when the Rock Drop will happen (it will be done twice, so likely 50% and 25% HP remaining?), so you can’t exactly fully prepare for it. As for the Bossbugs, they have some pretty high defense and 45HP each, so you never really want to see more than one summoned at a time (just break all the Locks to make it easier). Their attack doesn’t deal too much damage, though, so they’re not huge headaches, other than the situation with the Rock Drop above. That leaves the Sludge Spit, which seems to deal 50% of your current HP as damage, should it hit unblocked (lesser damage, if blocked).

Whenever the Sea Slug starts mixing in the two-spit version, it will deal a lot more damage, and could potentially do 100% of your current HP, if left unblocked. So, the moral of the story is to try and block all of the attacks, except for the Rock Drop, as that doesn’t matter. Resh’an is pretty good in this battle, as the Bossbugs are weak to poison (his normal element), plus he has a group heal and his ultimate is the best in the game. Don’t forget that, other than the Rock Drop, Lunar Shield is always a great ability to use, as it heals and can block a single attack from dealing damage.

(1 of 3) Serai’s Disorient is always great to help delay enemies’ turns.

Upon defeating the Sea Slug, you will unlock the Hey, that’s a reskin! trophy/achievement. Enter the cave it came out of to find a small chest that has a Rainbow Conch, then open the big chest for a scene. When the scene is over, you will obtain the Aetherwood Cork, Resh’an’s ultimate weapon.

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Guide Information
  • Platforms,
    PC, PS4, PS5, Steam, Switch, XB One, XB X|S
  • Genre
  • Guide Release
    30 August 2023
  • Last Updated
    3 November 2023
    Version History
  • Guide Author

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Sea of Stars is a retro-inspired Japanese role-playing game that pays homage to classics like Chrono Trigger and Super Mario RPG. Featuring a turn-based combat system that engages the player, as well as beautiful pixel work, the game will bring you back to those classics and fill you with nostalgia.

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