Brotherhood of the Sixth

The Brotherhood of the Sixth was a secretive cult-like organization that was devoted to the Sixth. It was presumably disbanded when the Sixth was killed by Naju.

History
When the Sixth allied with Ta'harok against Blackout, the Brotherhood of the Sixth became allied with Ta'harok by proxy. The Brotherhood accompanied the Sixth and Ta'harok to Darkmount to ensure that Blackout would be destroyed. The moment they boarded the city-ship, however, they were immediately surrounded by every single Makuta on board. The odds against them did not deter the Brotherhood from their cause; rather, they fought the Makuta all the way out of Darkmount and onto the Mata Nui II below.

With the Battle of Mata Nui II now fully underway, the Brotherhood of the Sixth fought against Blackout alongside some of Ta'harok's other allies, including Farpoint and the Toa Catastras. At some point, the Brotherhood of the Sixth merged (what little information is left of this battle does not state who they merged with - they either merged with themselves to create a new entity or they merged with the Sixth himself to give him more power).

Regardless, the Sixth was injured by Blackout and finished off by Naju later in the battle. If any members of the Brotherhood survived (unlikely), it is even more unlikely that the organization continued to exist without the Sixth.