Six Pillars

The Six Pillars (六柱 Roku no Hashira) are an elite group of assassins that are employed under the World Government and are stationed at the Tower of Judgment. They're main objective is too see that the execution of criminals goes smoothly and guard six different rooms in the tower.

Ultimately, the group was disbanded when all six members were defeated during the invasion of the Tower at the hands of the Red Wing Pirates alongside the Kosaka Clan