Saros Walkthrough — Full Story Guide with Boss Strategies and Endings

I finished my first full clear of Saros at about 22 hours. Then I spent another 15 unlocking the true ending. Here's the complete route through Carcosa with everything I learned along the way.

The Flow of a Run

Every run follows the same structure. You start in The Passage, pick your loadout, activate any Eclipse modifiers you want running, then descend into the biomes. There are five biomes total each with a boss at the end. Beat all five bosses in one run and you reach the endgame sequence.

Death sends you back to The Passage with your Lucenite and Halcyon intact. You lose your current weapon and any temporary buffs but the permanent upgrades from the Armor Matrix stay. This is the core loop. Die, upgrade, try again.

Biome One — Ashen Strand

Covered in detail in the first hours guide. The Warden of Ash is the boss. Key thing for this biome on repeat runs is speed. Once you know the enemy layouts you can clear it in about eight minutes skipping side paths. The weapon chest before the boss room always drops something useful so don't skip that.

Biome Two — The Verdant Hollow

The second biome is visually a complete shift. Gone are the ashen ruins. Now you're in an overgrown research facility with plant-like corruption everywhere. The enemies here are faster and some can teleport short distances.

New enemy type to watch for: the Warp Stalker. It teleports behind you every few seconds and fires a burst of three fast projectiles. The tell is a faint purple shimmer where it's about to appear. Dodge the instant you see the shimmer.

The biome two boss is the Conservator. It's a huge plant-corrupted machine that alternates between ground slam attacks and seeking vine projectiles. The ground slams create shockwaves you need to jump over. The vines can be shot down before they reach you. Focus one type at a time. I prefer shooting vines while strafing then punishing during the recovery after ground slams.

After the Conservator you get the grapple ability. This changes everything. You can now reach previously inaccessible areas in earlier biomes and the combat movement opens up dramatically. Grapple points glow orange.

Biome Three — The Sunken Depths

Underwater research station. Not actually underwater but the atmosphere is all flooded corridors and dripping ceilings. Enemies here use area denial attacks more heavily. Corruption pools on the ground, gas clouds, that sort of thing.

The grapple ability is essential here. Many arena sections have grapple points above the corruption pools. Stay airborne as much as possible.

Boss is the Drowned Oracle. This one was my wall. The Oracle summons copies of itself and only one takes damage. The real one has a faint golden outline around its head. Focus that one. The copies fire identical attack patterns so you need to track the real one while dodging everything else.

Phase two the Oracle stops summoning copies and instead floods the arena with seeking orbs while charging a massive beam attack. The beam is a one-shot kill. Interrupt it by dealing enough damage during the charge window. If you can't burst it down in time, the only cover is behind the pillars at the arena edges.

Biome Four — The Iron Bastion

Military compound. Tight corridors and shield-bearing enemies everywhere. This biome tests your parry ability more than any other. Shield enemies require a perfect parry to expose their weak point. You can't brute force through their shields.

The grapple ability gets upgraded here to a combat grapple. You can now pull smaller enemies toward you and stagger larger ones. This is incredibly useful for the shield enemies. Grapple them, they stumble, then unload into the exposed weak point.

Boss is the Warlord. Massive armored figure with a rotating shield that blocks damage from one direction. You need to constantly reposition to hit the unshielded side. The Warlord also summons shield-bearing adds during phase two. Kill them first or they'll body-block all your shots.

Biome Five — The Eclipse Spire

The final biome. Everything here is at maximum corruption. Eclipse modifiers are permanently active regardless of your settings. The visual effect is stunning. All the colors are inverted and pulsing.

No new enemy types here but all existing types appear in mixed configurations. You'll fight Warp Stalkers alongside shield enemies alongside area denial units. Prioritize the Warp Stalkers first. They'll backstab you while you're dealing with everything else.

Final Boss — The First Overlord

The First Overlord is the original colonist who accepted the Eclipse's power and became something no longer human. The fight has four phases and each phase introduces a new attack pattern on top of the existing ones.

Phase one is pure projectile patterns. Learn the rhythm and dodge through the gaps. Phase two adds melee charges that cover half the arena instantly. Phase three introduces corruption zones that spread over time. Phase four is everything at once with faster projectiles.

This fight took me eight attempts. The key is managing the corruption zones in phase three onward. If you let them spread too far you run out of safe arena space. Use area burst abilities to clear corruption pools if you have them. Otherwise, kite the boss around the edge of the arena to keep the center clear.

True Ending Requirements

After beating the First Overlord the game ends. But there's a true ending. To get it you need to do something specific during the final boss fight that the game never tells you about.

During phase four, when the Overlord's health drops below ten percent, it stops attacking and begins a charging animation. If you shoot it, the fight ends normally. If you instead walk up to it and interact, you get an alternative cutscene and the true ending path opens.

You also need to have found all five crew log collectibles across the biomes and exhausted all dialogue options in The Passage. Each crew member has a final conversation that only triggers after you've collected their associated logs. Do all of this before your final boss run.

The true ending adds about twenty minutes of additional content and fundamentally changes the meaning of the story. Without spoiling anything specific, it involves Nitya and the true nature of the Eclipse. It's worth the effort.