The Terran Purification League was an organization extant in the 23rd and 24th centuries. (Star Trek: Shadowstar Station)
One of its chief aims was the elimination of any non-Terran DNA from the human genome. The League looked upon the increasing number of Terran/non-Terran hybrids as abominations, taking interpretations of different faiths' holy books as justification for their worldview. They regarded Colonel Green as a prophet and a role model.
The League grudgingly worked together with other Terranocentric and human xenophobic organizations, such as Quattuor Anni.
In 2298, the League engineered the deaths of Andreas Kitabatu al-'Qalb's wife, Laurena Cytrynbaum, and their unborn child. Fifteen years later, Kitabatu al-'Qalb would avenge their murders. (Star Trek: Shadowstar Station: "A Separate War")