The Knights of Abomination are Toa from many different backgrounds and walks of life. Several of them used to be the perfect picture of a noble Toa, only to be twisted to Eepok's cause; others were hardened criminals long before meeting the Skakdi warlord. Ultimately, however, all 13 of these Toa met Eepok sometime during the 50,000 years prior to the events of "A City Divided", and were drafted by one means or another into the criminal's organization.
Each Knight controls a different element and due to experimentation, has immense control of that element (bordering on Nuva levels). The only thing that stops them ruling Metru Nui is the fact that they all hate each other. Additionally, they have been warped in the image of Eepok, a Skakdi. Thus they all have secondary powers along with their element and Kanohi along with hideous physical deformities.
The current roster of the Knights is: