The is a central plot device in the Sword Art Online: Alicization arc, serving as the absolute law of the Human Empire. It consists of a rigid set of rules established by the Axiom Church and Administrator to maintain order and prevent rebellion. Key Functions of the Taboo Index

Last updated: May 12, 2026

Ultimately, the most honest index of taboo is the one you refuse to write down. But in the age of total data, even that refusal becomes data. So search carefully—not because the information is dangerous, but because knowing the index changes what you are allowed to ignore.

A taboo is a social or cultural prohibition or ban on a particular activity, behavior, or topic, often considered objectionable or unacceptable by society. Taboos can be explicit, such as laws against incest or murder, or implicit, like the unwritten rules governing social interactions. The term "taboo" originates from the Tongan language, where it was used to describe something that was sacred or forbidden.