My first, and possibly only entry for the villain contest, Battle for the Gold Mask.

 

Zylor was sentenced to The Pit for his efforts to fight against the Toa. While there, he developed an immense hatred for them, as they were what caused him to become a hideous monster. Eventually, he manged to escape, and has used his time since to plot revenge on the Toa that caused him to be imprisoned.

 

Source: Zylor