Re:ZERO Arc 6 Guide: Every Trial of the Pleiades Watchtower Explained

If you ask longtime fans of Re:ZERO – Starting Life in Another World which arc truly changes the way they see Natsuki Subaru, many will immediately point to Arc 6 and the Pleiades Watchtower.

This place isn’t just another dungeon or magical tower. It feels like the final exam of everything Subaru and the Emilia Camp have learned throughout the series. Hidden deep inside the deadly Augria Sand Dunes, the tower was built by the legendary Sage Flugel to guard the seal of the Witch of Envy.

And let’s be honest: the Watchtower is one of the coolest and most mysterious locations in the entire story.

For Subaru’s group, reaching the tower isn’t about glory—it’s about survival. The memories and names of their allies were stolen by the Sin Archbishops of Gluttony, and the only hope of restoring them lies inside this ancient structure.

But entering the tower means playing by Shaula’s rules.

The Five Absolute Rules of the Watchtower

Guarding the tower is Shaula, a bizarre and loyal follower who believes Subaru might be the Sage she has waited centuries for. She enforces five iron rules.

Break any of them, and she transforms into a monstrous scorpion that hunts everyone inside.

The rules are simple—but terrifying:

• No one may leave the tower before clearing its trials.
• Each trial’s specific rules must be followed.
• The Taygeta Library must never be disrespected.
• The tower itself must not be damaged.
• The trials themselves may be destroyed.

That last rule is the loophole fans love talking about. It’s a classic Re:ZERO twist—what looks like a rigid system actually contains hidden exploits.

The Structure of the Pleiades Watchtower

The tower is divided into multiple layers named after stars in the Pleiades cluster. Each floor presents its own challenge or purpose.

Each floor tells a piece of the world’s ancient history, which is one reason Arc 6 feels like a massive lore drop for the entire series.

The Taygeta Trial – A Puzzle Only Subaru Could Solve

The first major trial takes place on the third floor, Taygeta.

At first the room appears empty. But once a monolith is touched, the entire space fills with stone pillars representing stars. The task sounds simple: touch the brightest star of the hero destroyed by Shaula.

Here’s the catch: the knowledge required doesn’t exist in the Re:ZERO world.

The answer refers to Orion, a constellation from Subaru’s Earth. The correct star is Rigel.

That moment perfectly captures Subaru’s role in the story. His otherworld knowledge—which normally feels useless—suddenly becomes the key to solving a trial no one else could pass.

Completing it unlocks the Taygeta Library, one of the creepiest and most fascinating locations in the entire arc.

The Library of the Dead

Inside the library are thousands of Books of the Dead.

Each book contains the full memories of someone who has died.

Yes, someone can literally read the life story of the dead.

For lore fans, this is incredible worldbuilding. But for Subaru, it becomes something much darker later in the arc.

Because eventually he finds his own book.

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Electra – The Impossible Duel with Reid Astrea

The second trial is pure combat.

Waiting on the Electra floor is the legendary first Sword Saint, Reid Astrea.

And he is exactly as terrifying as the legends say.

Reid doesn’t behave like a noble hero. He’s arrogant, rude, and ridiculously strong. Watching him repeatedly destroy Julius Juukulius is both brutal and fascinating.

This fight is important for Julius’s character. For a knight who built his identity on strength and honor, losing again and again to Reid shakes his confidence in a big way.

The twist comes when Roy Alphard, a Sin Archbishop of Gluttony, tries to devour Reid’s soul.

Instead of winning, Roy makes a catastrophic mistake.

Reid’s spirit is too powerful to consume, and it ends up taking over Roy’s body instead.

Classic Re:ZERO chaos.

The Final Trial – Volcanica and the Sage’s Qualification

At the top of the accessible tower lies the final test.

Here stands the Divine Dragon Volcanica, one of the legendary heroes who sealed the Witch of Envy 400 years ago.

But time hasn’t been kind.

Volcanica is senile and barely aware of what’s happening. The trial requires someone to prove they possess the qualifications of the Sage.

At the summit sits a monolith marked by the handprints of four ancient figures: Flugel, Reid, Farsale, and Volcanica.

Unexpectedly, the one who passes this trial is Emilia.

When she touches the monolith, the tower recognizes her as a candidate and grants her administrative authority over the Watchtower.

This moment feels huge because it hints that Emilia’s role in the world might be far bigger than we originally thought.

The “Amnesiabaru” Twist

Arc 6 is infamous among fans for one reason: Amnesiabaru.

One of the Sin Archbishops, Louis Arneb, manages to devour Subaru’s memories.

Suddenly the character we’ve followed for hundreds of chapters no longer remembers who he is.

Watching Subaru try to rebuild his identity from scratch while surrounded by people who insist he’s their hero is one of the most emotionally intense parts of the entire series.

Eventually he regains his memories by reading his own Book of the Dead, essentially confronting his entire life and all of his deaths.

It’s disturbing, brilliant, and very Re:ZERO.

Why the Pleiades Watchtower Arc Is So Loved

For many fans, the Watchtower arc represents Re:ZERO at its absolute peak.

It combines everything that makes the series special: deep lore about the world’s history, psychological torture for Subaru, clever puzzle solving, shocking twists involving the Sin Archbishops, and huge character growth for Emilia and Julius.

But more than anything, this arc forces Subaru to confront the question that has haunted him since the beginning.

Is he really the hero everyone believes he is?

The tower doesn’t just test strength or intelligence.

It tests identity.

And for Subaru, that might be the hardest trial of all.