Six powerful rulers who attempted to overthrow MATA NUI (1) and were condemned to the PIT for their crimes. The Barraki (Matoran for “warlord”) were originally allied in the LEAGUE OF SIX KINGDOMS and ruled a significant portion of the known universe. Desiring more, they attempted a revolution 80,000 years ago, but were defeated by an army led by the MAKUTA of METRU NUI. Before they could be executed, they were spirited away to the Pit by BOTAR. There they remained until the Pit was shattered by the GREAT CATACLYSM. The Barraki escaped but found that they were at the bottom of a strange ocean. Since only one of the six breathed water naturally, it appeared they were doomed.
But the mutagenic seawater of the region affected all the Barraki, severely mutating them and making it possible for all to survive at great depths. No longer able to breathe air, they carved out what empires they could beneath the waves and dreamed of revenge against Mata Nui (1) and the BROTHERHOOD OF MAKUTA. After the appearance of MAHRI NUI in their midst, they periodically hunted MATORAN for the fun of it.
All of that changed when the KANOHI IGNIKA drifted down into the Pit. The Barraki knew its power could transform them back to the perfect physical specimens they once were and make it possible for them to reclaim their kingdoms on the surface. They seized the mask, but then lost it after entrusting it to NOCTURN. The Barraki were then tricked by the TOA MAHRI into warring among themselves, while the Toa took advantage of the opportunity to search for the mask themselves.
The Barraki have since realized their error and have banded together once again to battle the Toa Mahri for possession of the Ignika. The six Barraki are PRIDAK, EHLEK, KALMAH, TAKADOX, CARAPAR, and MANTAX.
Source: BIONICLE Encyclopedia Updated