Why Did Al Fight Subaru in Re:Zero? Canon Explanation of Aldebaran's Betrayal

Spoiler Warning and Canon Scope

This article covers major events from Re:Zero Arc 9 as depicted in the original web novel and partially adapted into light novel volumes beginning with Volume 39. As of July 2026:

• The anime has not adapted Arc 9
• The manga is also behind these events
• The web novel is the most complete source for this conflict

All confirmed facts are drawn from primary material. Where interpretation is required, it is clearly labeled.

When Does Al Fight Subaru?

Arc 9: After the Vollachian Conflict

The conflict begins early in Arc 9, after the Vollachian conflict and Priscilla's death in Arc 8. Al turns on Subaru and Beatrice after returning to the original mission he had set aside while serving Priscilla.

In these chapters, Al:

• Uses his ability to trap Subaru and Beatrice
• Prevents Subaru from acting or escaping
• Openly declares hostility toward Subaru

This is the first time Al directly opposes Subaru in such a decisive and personal way.

What Exactly Happens in the Fight?

Al Turns on Subaru Without Warning

Al's attack is not gradual - it is immediate and deliberate. He isolates Subaru and Beatrice using a mysterious technique that creates a confined space, cutting them off from help.

During this confrontation, Al:

• Restricts Subaru's movement and options
• Refuses to cooperate or explain fully
• Treats Subaru as a target rather than an ally

The Key Line: Al's "Original Purpose"

The most important canonical statement comes during this confrontation, where Al says:

His original purpose is to remove Natsuki Subaru from this world.

This is not metaphorical. Within the context of the scene, it clearly implies killing or otherwise eliminating Subaru entirely.

This line is the foundation for understanding the conflict.

Why Did Al Fight Subaru?

Confirmed Canon Reason: A Mission to Eliminate Subaru

The only fully confirmed explanation is this:

• Al has an original mission
• That mission requires Subaru's removal from the world
• He resumes this mission during Arc 9

This is not speculation - it is explicitly stated in the source material.

What Is Al's "Original Purpose"?

Confirmed Facts

Canon reveals several key facts about Al:

• He remembers Japan and presents himself as another person from Subaru's world, though Arc 9 complicates what that means
• He possesses knowledge and abilities that don't match typical characters
• He has a pre-existing mission predating his service to Priscilla
• He had abandoned or delayed this mission for a long time

At the moment of the fight, Al effectively says:

• His time with Priscilla made him forget or ignore that purpose
• But now he is choosing to return to it

Important Detail: Priscilla's Influence

Al's loyalty to Priscilla had overridden his original goal. However, something changes in Arc 9 that pushes him back toward his mission.

This creates a clear internal conflict:

• Loyalty to Priscilla
• vs.
• Duty tied to Subaru's existence

Why Target Subaru Specifically?

Confirmed: Subaru Is the Key Variable

Al does not target anyone else - only Subaru.

From the story's framing, Subaru is:

• A unique anomaly due to Return by Death
• A person whose actions repeatedly reshape events
• Someone deeply tied to the Witch of Envy and the world's fate

Al's mission focuses solely on Subaru, which implies:

• Subaru's existence is directly tied to whatever outcome Al fears

Interpretation: Al Believes Subaru Is Dangerous

Based on available dialogue and context, Al appears to believe that:

• Subaru's continued existence leads to disastrous consequences
• Removing Subaru may be necessary to protect the world

This aligns with several narrative threads in Re:Zero:

• Subaru's power can distort timelines repeatedly
• His connection to Satella raises unresolved risks
• His influence grows exponentially over time

However, the story has not yet explicitly confirmed what exact outcome Al is trying to prevent.

The Role of Return by Death

Why Subaru Is Unique

Subaru's ability, Return by Death, allows him to:

• Reset time after death
• Change outcomes repeatedly
• Accumulate knowledge others cannot

From an outside perspective, this makes Subaru:

• Extremely powerful
• Unpredictable
• Potentially dangerous on a global scale

Possible Conflict with Al's Goal

If Al's mission is tied to preserving a "correct" world state, then Subaru's power directly interferes with that.

This would explain why:

• Al doesn't try to control Subaru
• He instead aims to remove him entirely

Al's Abilities and Why He Can Fight Subaru

Al Is Not a Normal Opponent

Al is one of the most mysterious characters in Re:Zero. During the fight, he demonstrates:

• Control over confined spaces or domains
• Combat awareness that matches Subaru's unpredictability
• Knowledge that suggests experience with unusual timelines

Possible Parallel to Subaru

Many readers note parallels between Al and Subaru:

• Both are isekai characters
• Both have abnormal abilities
• Both seem tied to larger unseen systems

This raises the possibility that:

• Al understands Subaru's nature better than anyone else
• He knows why Subaru must be stopped

However, this connection is not fully explained in canon yet

What Happens After the Fight?

Immediate Consequences

The fight does not resolve the conflict cleanly. Instead, it:

• Establishes Al as a direct antagonist (temporarily or conditionally)
• Introduces a new central mystery about Subaru's role
• Forces Subaru into a defensive position against someone he trusted

Long-Term Impact

This moment reshapes the narrative of Arc 9:

• Trust within the group is broken
• Al becomes unpredictable and dangerous
• Subaru must confront the possibility that his existence is a threat

Light Novel vs Web Novel Differences

Current Adaptation Status

• Web Novel: Fully covers the Al vs Subaru conflict (primary source)
• Light Novel: Has begun adapting Arc 9 starting with Volume 39
• Anime: Has not reached this arc as of July 2026

Important Note

The light novel may:

• Refine dialogue
• Clarify motivations
• Adjust pacing

However, the core event - Al attacking Subaru due to his mission - is consistent

What Is Still Unresolved?

Despite the clear conflict, several major questions remain unanswered:

1. Who Gave Al His Mission?

The story has not revealed:

• Who assigned Al's "original purpose"
• Whether it is self-imposed or externally commanded

2. What Exactly Happens If Subaru Lives?

We do not yet know:

• The precise outcome Al is trying to prevent
• Whether it involves Satella, the Witch factors, or something else

3. How Much Does Al Know?

Al clearly knows more than he reveals, including:

• Information about Subaru
• Details about the world's structure
• Possibly future outcomes

But the extent of this knowledge is still unclear.

The Bottom Line

Al fights Subaru in Re:Zero because he is following a hidden mission that requires Subaru's removal from the world. This is a confirmed canon statement in Arc 9. While the deeper reasoning behind this mission remains unresolved, the story strongly suggests that Subaru's existence poses a danger significant enough to justify extreme action. The conflict is not personal - it is driven by a larger, still-mysterious objective tied to the fate of the world.