Who is the last boss in "Street Fighter III"?

Gill is the last boss in Street Fighter III. He is the series’ principal antagonist and the leader of the Illuminati, the secret organization that replaces M. Bison’s Shadaloo as the central threat in this chapter of the franchise.

Gill’s design makes him especially memorable: one side of his body is red and the other is blue, reflecting his ability to use fire and ice attacks. He can also resurrect himself after being defeated, making the climactic fight unusually punishing for arcade players. Gill was not selectable in the original arcade versions, although console releases later allowed him to be unlocked.

The wording can cause minor confusion because Street Fighter III exists in several versions. Gill is the final opponent for every character in New Generation and 3rd Strike, while 2nd Impact includes character-specific exceptions and a secret Akuma encounter. Even with those variations, Gill is the canonical final boss associated with Street Fighter III.