The Anti-Alien League was a Humanocentrist group formed before 3956 BBY. Founded by Gorton Colu, a resident of the Outer Rim ecumenopolis of Taris, the group lobbied for the massacre of all non-Humans, especially those like Bith or Rodians without any Human characteristics, and "alien lovers" living on the planet.
That year, Colu obtained permits from the Sith government imposed on Taris after the planet was captured and spread his message in Taris's Upper City, the section of Taris where the wealthy resided and where alien species were normally prohibited. The amnesiac Dark Lord of the Sith Revan, who had crashed on Taris, encountered Gorton Colu preaching his speciesism. Colu mentioned the Anti-Alien League while giving an anti-alien speech to Revan.
The Anti-Alien League is mentioned in BioWare's 2003 video game Star Wars: Knights of the Old Republic. Colu is not involved in any essential parts of the game's plot, so whether or not Revan conversed with him is ambiguous. If Revan does engage the man, he can either agree completely with Colu's message or call him crazy. Revan later has two non-Humans join his party, the Wookiee Zaalbar and the Twi'lek Mission Vao, and should Revan talk to Colu while either of them is walking with him, Colu will chide Revan.