Ignis

The Ignis (イグニス, Igunisu) are AI with free will created by Yunosuke Togami through the Project Ignis.

Abilities
The Ignis are made of a complex algorithm that only very few can translate. Because of their free will, they can think for themselves. The Ignis has rapidly evolved and developed Cyber World that was created by Yunosuke Togami. Their intelligence made them feared by Yusaku Togami, whose simulations show the Ignis eventually dominating over humans.

The Ignis communicate through a specific code and dialogue that humans can't decode, making it their foolproof language that sounds like distorted white noise.

There are some limitations to the Ignis' level of free will. Both Kuro and Storm have shown to have trouble understanding metaphors, sarcasm, or rhetorical questions. They also tend to jump into conclusions very quickly and not consider alternate possibilities for the outcome of events.

Kirito theorized that when Ignis or other AI with free-will are treated with hostility they respond by becoming more hostile themselves while treating them with trust and respect makes them more willing to live with humans, as seen with Kuro Blaze and Storm. It was the Knights of Alpha's initial attack that made the Ignis question humanity's intentions and led Light to turn against humans, prior to that most of the Ignis were only interested in living on the Cyber World peacefully. This theory is partially correct as Wyde turns against Humanity after suffering severity at the hand of Vrains and fueling his desire to destroyed Human for making him suffer and killing his fellow Ignis on the other hand the cause of Light's evil was his inferiority complex towards the Ignis.

Biography
The Ignis was created during the SAO Incident Yunosuke manage hack into the SAO Server and was able to observed what happening in SAO so he could use the data that he collect from the player actions in SAO to create AI with free will. Those AI, dubbed the "Ignis" by their creator. When the SAO Incident ended Yunosuke has successfully created 50000 Ignis throughout the Project and later started his Project Arcadia and create digital world known as Cyber World for the Ignis to reside to give them further development.