Warning Spoiler Alert: This article or section contains details about plotlines not covered in the anime. Do not proceed unless you wish to be spoiled.
Eugeo triggering the Seal of the Right Eye S03E10

Seal of the Right Eye on Eugeo

The Seal of the Right Eye (右眼の封印, Migime no Fūin?) is a seal that prevents or discourages the people of Underworld from breaking any rules that are set upon them, including laws, social norms, or any instruction imposed on them by someone they may consider higher than themselves, such as a parent or god.

Knowledge of this Seal, or even the fact there is a restriction on the wills of people to begin with, is not commonly known, though there are some people that show signs of awareness of the Seal, including Azurika, who claimed that she was unable to break the Seal which Eugeo did.


The Seal was likely created by a person from a large company monopolising the domestic defense industry or a foreign arms manufacturer who infiltrated Rath to sabotage their project. However, as the person only delayed the project by implanting such an inhibitor into the system, instead of just destroying the Light Cube Cluster, it is likely that the person's true goal is only to slow the project down in preparation for stealing Project Alicization's experimentation results, as well as the Light Cube Cluster, which houses the Artificial Fluctlights themselves, for their own gains.[1]


The Seal works by inducing great pain onto a human's right eye whenever they even attempt to think about questioning or breaking any rules that they believe have authority, to dissuade them from questioning or acting out against an imposed rule.

Eugeo seeing CODE 871 on his right eye - S3E10

The seal from an Underworld inhabitant's point of view

If a person continues to think about the rules and even decides to attempt to break them, the Seal paralyzes their body, with the words "SYSTEM ALERT CODE: 871" in English appearing on their right eye, thus preventing them from continuing to take action.

The Seal's effect can be avoided through exploiting loopholes in the rules that the residents regard as authority, and thus some residents, especially nobles, continuously search for such loopholes to abuse for their desires.

Blood spilling from Eugeo's eye after breaking his seal as he readies a Sword Skill - S3E10

Eugeo having broken the seal

This Seal, however, is not absolute as both Eugeo[2] and Alice Synthesis Thirty[1] were able to break free from the Seal's hold by overwhelming it with willpower when extreme situations provoked them to greatly question their sense of judgement. If the person manages to overwhelm the Seal, this leads to the destruction of the eye, after which the person is able to freely break the rules imposed on them, if it is within their will to do so. It is also possible to eliminate the seal by mechanically destroying the right eye of an Artificial Fluctlight's avatar, such as in the case of Iskahn.[3]

Raios's Fluctlight experiencing glitches due to Raios's internal conflict - S3E10

Raios's Fluctlight collapsing

On the other hand, the Artificial Fluctlights who lack the willpower to overpower the Seal but cannot bring themselves to stop thinking about breaking them, such as in Raios Antinous's case, may collapse from the pressure, even if their avatars do still have Life remaining.[2]


Start a Discussion Discussions about Seal of the Right Eye

  • Kirito's eye didn't explode

    8 messages
    • Does kirito break the seal of the right eye? Because Alice and eugeo broke it.
    • Elfontheshelffrosty2 wrote:Does kirito break the seal of the right eye? Because Alice and eugeo broke it. Did you read the rest of this thre...
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    • The problem is, it usually is shown when there's an actual broken file link on the page...
    • Is there a time when this page have broken file link? Anyway, I don't know if Wikia automatically run maintenance check and add t...
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