Re:ZERO Season 4 Part 2: The Third Trial of the Watchtower Rules and Limitations Explained
As a fan, this is exactly what makes Re:ZERO so addictive.
The Third Trial isn’t memorable because of one spectacular attack. What makes it interesting is the uncomfortable idea behind it: what happens when an ancient system continues operating long after the people who created it are gone?
That question becomes especially important on the first floor, where the legendary Divine Dragon Volcanica stands between the challengers and the secrets of the Watchtower.
The Pleiades Watchtower Was Never Meant to Be Easy
The Watchtower is one of the most mysterious locations introduced during the Arc 6 storyline. It was created centuries ago and is closely connected to the legendary figures of Re:ZERO’s past, including Sage Flugel, Reid Astrea, and Volcanica.
For Subaru and the others, reaching the tower isn’t the end of the problem. It’s the beginning.
The expedition becomes trapped inside a place where ordinary logic doesn’t always apply. The tower has its own rules, its own trials, and its own methods of dealing with anyone who breaks them.
And honestly, that’s one of the things I love most about this part of Re:ZERO.
The characters can’t simply walk into the Watchtower, defeat a boss, and collect the reward. Every decision has a price.
The Five Major Rules
The Watchtower’s basic restrictions can be summarized like this:
- Leaving the tower without completing the Trials is forbidden.
- Breaking the rules of the Trials is forbidden.
- The tower’s libraries and their contents must not be violated.
- Damaging the Watchtower itself is forbidden.
- Destroying the Trials themselves is not forbidden.
That final rule is the really interesting one.
The fifth rule creates a loophole that changes the way the entire Watchtower should be understood. Instead of assuming that every Trial must be completed exactly as intended, the characters eventually realize that the Trials themselves can potentially be challenged at a much more fundamental level.
For a series like Re:ZERO, that feels almost perfect.
The solution isn’t necessarily to win the game. Sometimes, you have to break the game.
What Makes the Third Trial Different?
The Third Trial takes the story to Electra, the first floor of the Watchtower.
Compared with the other challenges, this part feels much less like a conventional test and much more like an encounter with an ancient system that has stopped functioning properly.
At the center of it is Volcanica, the Divine Dragon.
Volcanica is not some random monster guarding treasure. He is one of the legendary beings connected to the events of four centuries ago. His history reaches back to the era of the Great Calamity and the sealing of Satella.
That history is important because Volcanica’s greatest weakness isn’t his strength.
It’s his mind.
Volcanica Is Powerful — But He Is No Longer the Dragon of Legend
This is probably my favorite aspect of the Third Trial.
The characters are dealing with something that was once almost godlike, yet centuries of isolation have left Volcanica severely diminished mentally.
Instead of functioning like a perfectly rational guardian who explains the rules and waits for the correct answer, he behaves like a broken remnant of an ancient age.
His memories are fragmented.
His understanding of the present is unreliable.
And his instincts can be terrifying.
That creates a fascinating contradiction: the strongest being in the room may also be the least capable of understanding what is actually happening.
For the challengers, that’s a nightmare.
You can’t simply negotiate with someone who isn’t fully aware of the current situation. At the same time, trying to overpower Volcanica is an incredibly dangerous proposition.
The Real Limitation: You Can’t Just Fight Your Way Through
One of the biggest mistakes someone could make when looking at the Third Trial is assuming that it’s simply another boss battle.
It isn’t.
Even if the challenger has enough power to survive Volcanica’s attacks, physical strength alone doesn’t automatically solve the problem.
The Divine Dragon possesses overwhelming physical and magical abilities. His attacks can turn the battlefield into a disaster zone, while his Dragon’s Breath represents an enormous threat to anyone caught in its path.
But there is another problem.
The Watchtower itself has rules.
The challenger has to survive without simply destroying everything around them. They also need to reach the mechanism or stone plaque associated with the Trial and satisfy the conditions necessary for recognition.
This is where Re:ZERO does what it does best: it turns a fight into a puzzle.
| Challenge | Why It Matters |
|---|---|
| Volcanica’s power | Direct confrontation is extremely dangerous |
| His damaged memories | Negotiation becomes unpredictable |
| Watchtower rules | Reckless actions can have catastrophic consequences |
| The stone plaque | Raw strength isn’t enough to guarantee success |
| The Fifth Rule | Creates a potential loophole in the Trial system |
Emilia’s Role Makes the Trial Even More Interesting
For me, one of the most compelling elements of this storyline is Emilia’s involvement.
Emilia has always been treated unfairly because of her resemblance to the Witch of Envy. Characters project their fears and memories onto her before they even get to know her.
The Third Trial plays with that idea in a particularly interesting way.
When Volcanica encounters Emilia, the resemblance can trigger fragments of his ancient memories. Instead of seeing only the person standing in front of him, the Dragon is confronted with echoes of the past.
That creates a strange emotional tension.
Emilia isn’t simply fighting an ancient dragon. She’s standing in front of a living piece of history that can barely distinguish the present from the past.
And that’s why I think the psychological side of this encounter is more important than the spectacle.
The Fifth Rule Changes Everything
The secret behind the Watchtower’s fifth rule is arguably one of the most important pieces of the entire puzzle.
If the Trials themselves can be destroyed, then the characters aren’t necessarily required to treat them as sacred, perfectly designed challenges.
That’s a huge distinction.
Imagine being trapped inside a game where the rules say you must complete three impossible levels. Then you discover that the rules never actually said you couldn’t destroy the levels themselves.
That’s essentially the kind of loophole that makes Re:ZERO’s world-building so satisfying.
The characters are rewarded not only for strength or courage, but for understanding the system they’re trapped inside.
And Subaru’s journey throughout Re:ZERO has repeatedly emphasized exactly that principle.
Why the Third Trial Feels So Different From a Typical Anime Battle
If this were a more traditional fantasy anime, the solution would probably be obvious.
Find the strongest character.
Power up.
Defeat the guardian.
Win the Trial.
Re:ZERO doesn’t work that way.
Here, the characters have to deal with:
- An ancient magical system
- Incomplete information
- A deteriorating guardian
- Strict supernatural rules
- Hidden loopholes
- Psychological pressure
- The consequences of making the wrong decision
That’s what makes the Re:ZERO Third Trial so interesting.
The enemy isn’t just Volcanica.
The real enemy is the system itself.
Where to Read Re:Zero Web Novel Arc 6 English Translation (Full Guide)
What Happens After the Trial?
Successfully dealing with the Third Trial has consequences far beyond simply opening another door.
The Watchtower’s administrative structure becomes extremely important, while the fate of Shaula and the tower’s ancient mechanisms becomes increasingly complicated.
Shaula’s existence is especially tragic when you look at it from a wider perspective.
She has spent centuries carrying out her role, waiting for the return of the person she considers her master. Her loyalty is almost touching until you realize just how cruel that endless waiting actually is.
That’s another reason the Watchtower works so well as a setting.
Everything has history.
The characters aren’t exploring an abandoned building. They’re walking through the remains of decisions made hundreds of years ago.
And sooner or later, those old decisions collide with the present.
Final Thoughts: The Trial Is Really About Understanding Re:ZERO
The Third Trial of the Pleiades Watchtower is one of those Re:ZERO storylines that becomes more interesting the more you think about it.
On the surface, there is an ancient tower, a legendary Divine Dragon, deadly supernatural rules, and a seemingly impossible challenge.
Underneath all of that, however, is something much more interesting.
It’s a story about systems that outlive their creators.
Volcanica is trapped in the past. Shaula is trapped by her duty. The Watchtower is trapped by ancient rules. And the modern characters are forced to navigate all of it without fully understanding what happened four hundred years ago.
That’s classic Re:ZERO.
The series constantly asks whether survival comes from becoming stronger or from learning how the world actually works.
And the Third Trial strongly suggests the latter.
You don’t always beat Re:ZERO’s strongest obstacles by overpowering them. Sometimes you survive by finding the one rule nobody thought to explain.
That is why the Pleiades Watchtower remains one of the most fascinating locations in the series — and why the Third Trial deserves far more attention than simply being labeled another boss encounter.
For fans waiting to see how the Watchtower storyline translates into anime form, this is exactly the kind of material that could make Re:ZERO Season 4 Part 2 especially memorable: ancient mysteries, broken legends, psychological tension, and a battle where understanding the rules may be more important than winning the fight.
