Nidhiki

Nidhiki was once a Toa of Air but was later transformed into an insectoid monster. He was a member of the Dark Hunters.

Toa
Nidhiki came to Metru Nui as one of the eleven Toa who fought the Kanohi Dragon, along with Toa Lhikan. Like the rest of his team, he stays as one of the city's resident Toa. He showed great teamwork in defeating powerful enemies like Dark Hunters and Tuyet.

Two thousand years later, the city's leader, Turaga Dume, refused to allow the Dark Hunters to build a base in Metru Nui. The Dark Hunters attacked the city in retaliation, and hundreds of Toa (led by Lhikan) rallied to the city's defense. The fighting went on for months, with heavy casualties on both sides. Seeking to save his own skin, Nidhiki struck a deal with a Dark Hunter, named Lariska, and agreed to lead the Toa into a trap. However, Lhikan found out and set a trap of his own. This action ended the war with the Toa as victors, and Lhikan removed all Dark Hunters from the city – Nidhiki along with them.

Dark Hunter
With nowhere else to go, Nidhiki joined the Dark Hunters as an instructor, teaching others – including the Piraka Vezok – from his experience as a Toa. Wanting to be more than a teacher, he asked to be sent on missions. He got his wish, but to his displeasure is paired with a rather dim, brutish Hunter named Krekka. From the perspective of the Hunters' leader, "The Shadowed One", this was a good partnership: Krekka could be effective if he follows Nidhiki's plans, while Nidhiki could be kept in line by Krekka's loyalty to the Hunters.

However, Nidhiki continued to want more, dreaming of being a hero again. When Roodaka came to the Hunters seeking training, he offered to reward her if she would help him escape the Hunters. Instead, she alerted the Shadowed One to Nidhiki's plans and "earned" her training by mutating him into an insectoid monster, ensuring that he could never be accepted anywhere except the Dark Hunters. Ironically, Nidhiki was insectophobic.

Hundreds of years later, Nidhiki and Krekka were sent back to Metru Nui on a mission for Makuta. Their task was to retrieve six Great Kanoka Disks and to get Toa Lhikan out of the way - an assignment Nidhiki enjoyed, as he still held a grudge over his banishment. While the two were able to capture Lhikan, he had already chosen replacements and set them on the path to become the Toa Metru. Nidhiki blackmailed one of the Matoran, Ahkmou, into helping him get the Great Disks, but this failed as the Toa Metru were able to get to them first. Nidhiki and Krekka continued to hunt the Toa Metru until Makuta decided to face the Toa himself, in order to increase his power quickly he absorbed the two Hunters and his pet, Nivawk, into his body, killing them.

Tools and Powers
As a Toa of Air he controled the element of air. He carried an Air Scythe and wore the Kanohi Volitak, but he lost the ability to use it when Roodaka mutated him.

As a Dark Hunter, Nidhiki had a pair of pincer claws, and he could fire Kanoka disks from his mouth. He also had the ability to fly.

Trivia

 * The beach Nidhiki was mutated on is named after him. It is now called Nidhiki Beach.
 * Nidhiki had a phobia of multi-legged insectoid Rahi, which made his transformation all the more frightening for him.