Re:ZERO Arc 6: Why Subaru Cannot Use Return by Death Effectively?

For most of Re:ZERO, watching Natsuki Subaru use Return by Death feels like watching a guy slowly evolve into the ultimate survival strategist. He dies, suffers, learns, adapts, and eventually starts outsmarting enemies who should realistically crush him in seconds. By the end of earlier arcs, Subaru is not just surviving anymore — he is leading people, making impossible calls, and carrying entire battles through pure mental endurance.

Then Arc 6 happens.

And honestly, as a longtime fan, the Pleiades Watchtower Arc feels like the series taking a sledgehammer to everything Subaru built. Not because he suddenly becomes weak again, but because Arc 6 perfectly exposes the ugly truth behind Return by Death: the ability only works when Subaru himself is mentally stable enough to use it properly.

That is why Arc 6 is so terrifying. It does not counter Subaru with brute force alone. It attacks his identity, his memory, his confidence, and even his soul itself.

Arc 6 Turns Subaru Back Into Arc 1 Subaru

The biggest reason Return by Death becomes nearly useless is simple: Subaru loses his memories.

Once he enters the Taygeta Library, the version of Subaru fans watched grow for multiple arcs basically disappears overnight. The confident strategist who defeated Sin Archbishops and survived impossible timelines gets erased, leaving behind a confused teenager who has no clue what is happening around him.

And that changes everything.

Before the memory loss, Subaru understood:

• Who he could trust.
• How his allies fought.
• How dangerous the world truly was.
• How to emotionally handle Return by Death.

After the amnesia, he knows absolutely nothing.

That is what makes Arc 6 feel so different from previous loops. Earlier arcs usually rewarded Subaru’s persistence. Every death gave him valuable information he could use later.

But inside the Watchtower, Subaru cannot even process the information correctly.

He does not know why Emilia cares about him, why Beatrice trusts him, why Julius acts friendly, or whether any of them are secretly trying to kill him.

Instead of solving problems efficiently, his loops become trapped in paranoia and confusion.

As a fan, this part of the arc was honestly painful to watch, but in the best possible way. Tappei Nagatsuki basically asks the audience one brutal question: if Subaru lost all the development fans loved him for, would he still be Subaru?

That idea alone makes Arc 6 one of the darkest arcs in the entire series.

The Psychological Damage Is Worse Than the Physical Deaths

One thing many viewers underestimate is just how mentally destroyed Subaru becomes during Arc 6.

Amnesia Subaru constantly hears stories about the “heroic” Natsuki Subaru — the guy who defeated the White Whale, saved Sanctuary, inspired Emilia, and survived impossible odds.

But internally, he feels like a fraud.

And honestly, his reaction feels incredibly human.

Imagine waking up surrounded by insanely powerful people who all love a version of you that you do not remember being. Most people would probably become insecure too. Subaru starts viewing his old self almost like a rival he can never live up to.

That creates massive emotional paralysis.

Instead of using Return by Death confidently, he becomes terrified of making choices at all. Every failed loop pushes him deeper into self-hatred, and eventually he starts emotionally disconnecting from everyone around him.

That is the genius of Arc 6: the real enemy is not just the Watchtower — it is Subaru’s collapsing sense of self.

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Louis Arneb Completely Corrupts the System

If the amnesia was not already enough, Arc 6 adds another horrifying twist with Louis Arneb.

This is where Return by Death becomes genuinely compromised for the first time in the series.

Louis does not just attack Subaru physically. She invades him psychologically and spiritually. Once she learns about Return by Death, she effectively becomes a parasite living inside Subaru’s existence.

And that completely ruins Subaru’s greatest advantage: privacy across timelines.

Normally, Subaru alone remembers failed loops. That secrecy allows him to gather information safely.

But now Louis experiences parts of it too.

That means Subaru’s only safe space is gone.

Even worse, Louis manipulates his emotions from inside his own mind:

• Amplifying fear.
• Worsening paranoia.
• Causing hallucinations.
• Indirectly leading to horrific outcomes.

The Meili loop still remains one of the most disturbing moments in Re:ZERO because Subaru genuinely loses control over himself. Watching him question whether he is becoming a monster was terrifying.

Arc 6 basically weaponizes Subaru’s own ability against him.

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The Checkpoint Placement Is Pure Evil

Another underrated reason Subaru struggles so badly is the checkpoint itself.

Return by Death has always had one hidden weakness: Subaru never chooses the save point.

And Arc 6 gives him arguably the worst checkpoint in the series.

He respawns without memories, inside an active crisis zone, surrounded by suspicious allies, while multiple disasters are already happening simultaneously.

There is no preparation phase.

Earlier arcs usually gave Subaru time to investigate, build trust, and slowly gather information. In the Pleiades Watchtower, he wakes up and immediately gets thrown into chaos.

Sometimes he dies within minutes.

That completely destroys the trial-and-error rhythm Return by Death normally relies on.

The short loops make meaningful progress almost impossible.

Too Many Threats Exist at the Same Time

Another thing that makes Arc 6 unique is the sheer number of overlapping disasters.

Subaru usually succeeds when he can isolate one major problem and slowly solve it.

But the Watchtower throws multiple nightmare-level threats at him simultaneously:

1. Reid Astrea destroying anyone in his path.
2. Massive Witchbeast swarms invading the tower.
3. The tower’s deadly rules punishing mistakes instantly.
4. The Gluttony Archbishops attacking from multiple directions.
5. The terrifying shadow of Satella acting like a world-ending timer.

This is why so many loops feel hopeless.

Even if Subaru solves one problem, another immediately wipes the group out.

It almost feels like the arc was specifically designed to mathematically counter Return by Death itself.

And honestly, that is why so many fans love it.

Arc 6 Is the Ultimate Reality Check for Return by Death

A lot of anime and isekai series treat time-loop abilities like unbeatable cheat powers.

Re:ZERO does the exact opposite.

Arc 6 proves that Return by Death is not some flawless win button. It is only as effective as the person using it. If Subaru loses his confidence, identity, emotional connections, or ability to trust himself, the power falls apart too.

That is what makes the Watchtower Arc so special.

It strips Subaru down to his absolute worst state and forces him to rebuild himself again from nothing.

Not physically.

Emotionally.

And in many fans’ opinions, that is exactly why Arc 6 contains some of the best writing in all of Re:ZERO.