Ignis

The Ignis (イグニス, Igunisu) are AI with free will from the Yu-Gi-Oh! VRAINS anime, created by Dr. Kogami through the Hanoi Project. They created and inhabit the Cyberse. According to Varis, the Ignis are out trying to conquer the network. For this reason, the Knights of Hanoi led by Varis are trying to kill all the Ignis with aid in this mission from Dr. Kogami's avatar. According to Ai, one of the Ignis, they don't want anything to do with humanity and would prefer to live peacefully in their own world.

Currently, the Ignis are missing, and two of the Ignis and their humans are working together to find the other four.

Appearance
Ignis are humanoid life forms with disproportionate bodies that are smaller than a Duel Disk, though they can change their size and appearance at will. In their natural height, the list goes (from tallest to shortest): the EARTH Ignis, Flame/Ai (same height), LIGHT Ignis, WATER Ignis, and WIND Ignis. They can also shape-shift into monstrous forms when expressing strong emotions.

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 quickly evolved to create their own world in the network called Cyberse World and the Cyberse Monsters. Their intelligence made them feared by Dr. Kogami, whose simulations show the Ignis eventually dominating over humans. Ignis can regenerate by recovering their data unless some of the data is stored in another program or avatar. So far, however, the Ignis are unable to leave the network completely and must remain connected to a source, such as a Duel Disk.

In Ai's flashback, each of the Ignis recognize themselves with an element with their own sector of Cyberse portraying that element. Their are parallel to the Attributes of Duel Monsters, excluding DIVINE. Their elements seem to tie into what monster they can shape-shift into, an example being Flame, the Ignis associated with FIRE, becomes a fire demon when he's very excited. The Ignis communicate through a specific code that humans can't decode, making it their foolproof language.

There are some limitations to the Ignis' level of free will. Both Ai and Flame 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.

Etymology
Ignis means "fire" in Latin. Dr. Kogami named them after the theft of fire legends, in which the forbidden fire allowed humans to rapidly evolve.

History
Dr. Kogami kidnapped six children, among them Yusaku, Spectre, Takeru and Jin and forced them to Duel so he could use the data collected from those duels to create AI with free will. Those AI, dubbed the "Ignis" by their creator, created the Cyberse World where they lived together away from humans and also created the Cyberse Monsters. A product from the Ignis creating the Cyberse World was Data Material, which processed data thousands of times faster than the current data processor. However, the Ignis soon developed more rapidly than Dr. Kogami had originally planned. Through simulations of their growth, Dr. Kogami could only find that they would overthrow humanity and so created the cyber-terrorist group the Knights of Hanoi to destroy them.

Many of the Ignis were captured by the Knights of Hanoi. One of the Ignis, the "Dark Ignis", tried to rescue the others, but he was caught and eaten by "Cracking Dragon". He survived, but lost most of his data (including his body) and was reduced to an eye.

After the Dark Ignis hid Cyberse, the remaining five were freed from their binds and discussed if they should share their technology with the humans in order to establish peace between the races. However, an unknown force attacks Cyberse, hitting its weaknesses and destroying the Ignis homeworld. The Ignis were forced to flee to the network and have so far not been seen. The only one confirmed to have gone to the real world is Flame, the Fire Ignis, who found his human, Takeru Homura.

Hanoi Arc
The injured Ignis eventually escaped into Den City where he was later captured by Yusaku Fujiki (Playmaker) and Kolter. As he is an AI and an eye at the time, they decided to nickname him "Ai". Ai later reclaims his body from the Knights of Hanoi after Playmaker defeats Varis.

After his duel with Faust, Yusaku grows suspicious of Ai. Ai also starts behaving suspiciously, apparently manipulating Playmaker into blatantly ignoring the Knights of Hanoi whenever it seems like they're about to explain why they're hunting the Ignis. In the Hanoi Tower incident, the Hanoi Tower threatened to wipe out the entire network, destroying the Ignis in the process. Varis then explains the origins of Ai and the other Ignis, leading Yusaku into more suspicion about the Ignis. Ai admits that he only lied so that he can survive and return to the other Ignis.

Unnamed Arc
Three months after the Hanoi Tower incident, Ai reopens Cyberse. However, the world is barren and none of the Ignis were found. Flame, one of the Ignis that escaped, is assisted by Takeru and later Ai and Yusaku in order to find the other four. The unknown assailant that took Jin's data seems to be using Ignis programs, one identified to be the WIND Attribute.