As a Matoran, Nidhiki lived on the Tren Krom Peninsula.
After becoming a Toa, Nidhiki was forced to learn to attack from the shadows due to the inhospitable nature of the Tren Krom Peninsula, in order to maximize his survival chances.
Nidhiki was one of the eleven that answered the summons to protect Metru Nui from the Kanohi Dragon. After the defeat of the Rahi and its delivery to Xia, those eleven Toa chose to stay and protect Metru Nui and became the Toa Mangai.
Around 3,500 years ago, while most of their teammates were out on missions, Nidhiki helped Lhikan investigate the mysterious attacks on the Matoran of Metru Nui. Their teammate Tuyet told them that the Dark Hunters believed she possessed the Nui Stone, and were responsible for the deaths of the Matoran as a threat to her. Nidhiki fought and defeated Devastator and later helped Lhikan to work out that Tuyet was actually the cause of the deaths, joining Lhikan in confronting her. After her defeat, Nidhiki tried to obtain the Nui Stone for himself, but Lhikan intervened just in time to stop him from making the same mistake.
War with the Dark Hunters
During the Toa/Dark Hunter War Nidhiki was assigned to protect Turaga Dume, though he grew bored with guard duty and slipped out, joining Lhikan on his rounds. While searching Ga-Metru by himself, Nidhiki was confronted and cornered by the Dark Hunter Lariska, who proposed that Nidhiki betray the city in exchange for a leadership position in it. Tempted by dreams of conquest, Nidhiki agreed to lead the Toa into the ambush so the Hunters could win the war. Lhikan sent Nidhiki to meet some supply boats the next night, but Nidhiki left without hearing where, and instead met with Lariska and completed their agreement. The next morning, Nidhiki told Lhikan and the other Toa that the Dark Hunter's base was hidden in the Canyon of Unending Whispers, and that every Toa was needed in order to end the war. Nidhiki led the Toa into the valley, where they were surrounded by Dark Hunters. However, Lhikan had discovered his betrayal, and prepared a counter-ambush with Toa reinforcements, which had arrived on the supply boats Nidhiki was supposed to have visited. With his betrayal revealed, Nidhiki was told to leave, or face execution.
The Shadowed One made Nidhiki a trainer of new recruits, though Nidhiki believed himself to be above the position. One of his trainees was the Skakdi Vezok, and Nidhiki tried to teach him how to discreetly open a safe; Vezok instead smashed it to pieces, and Nidhiki chose to avoid confrontation by passing him. Upon the recruitment of Poison, Nidhiki also trained him, teaching him how to use his power.
Nidhiki was responsible for preparing a team to capture the Makoki Stone from a heavily defended fortress. He got easily bored with training the team, and was especially annoyed with one trainee, Krekka. He later met with the Shadowed One, who decided to send him on a mission with a partner. Nidhiki was convinced that it would be Lariska; however the Shadowed One instead paired him with Krekka. Joined with Lariska, their first mission was to steal three prototype launchers from a Matoran village on Nynrah. Lariska went ahead to distract the Toa there, while Nidhiki and Krekka retrieved the launchers. Nidhiki wanted to bring one to the Shadowed One and keep the other two for himself, offering one to Krekka as a bribe. Krekka threatened to turn him in, however, and Nidhiki was forced to give all three to the Shadowed One.
Return to Metru Nui
Nidhiki eventually returned to Metru Nui, along with Krekka and Eliminator, to assist Teridax, the Makuta of Metru Nui, who was impersonating Turaga Dume. Nidhiki and Krekka tracked Nidhiki's old teammate Lhikan as he retrieved Toa Stones to make a new team of Toa, ambushing him in the Great Temple, though the Toa of Fire managed to escape. The pair caught up with him after he delivered the Toa Stones to the destined Toa Metru, and attacked him in Vakama's forge. Nidhiki threatened to kill Vakama, holding him over the forge, giving Krekka the opening he needed to defeat Lhikan. Though Lhikan surrendered, Nidhiki dropped Vakama anyway, forcing Lhikan to sacrifice his own safety to save the Ta-Matoran. Nidhiki and Krekka captured the Toa, and took him to the Prison of the Dark Hunters. Nidhiki then convinced Ahkmou to undermine the Toa Metru and find the Great Disks so the Toa could not defeat the Morbuzakh, paying the Matoran for his services. Nidhiki provided Ahkmou with five notes that would lead the other five Matoran who knew the locations of the Great Disks into traps set by himself. While Vakama saved Nuhrii from Morbuzakh vines, Nidhiki sabotaged the vat controls. However, after three of these Matoran were rescued by the Toa Metru, Nidhiki became impatient, and intimidated Ahkmou by introducing him to Krekka.
The duo later returned to the Coliseum, and attempted to kidnap the Toa Metru, trapping three of them. The other three escaped in chutes, and the Dark Hunters tried to capture them by coercing Kongu to reverse the chute flow. The Toa successfully evaded the Hunters, who soon caught up with them and battled the Toa onboard an Airship in Le-Metru. After Vakama teleported Krekka out of the ship, the Toa left Nidhiki, who decided to find Krekka rather than pursue them. Nidhiki and Krekka made another attempt to capture Nokama, Vakama, and Matau in Po-Metru, but were stopped by a stampede of Kikanalo. Afterwards, Matau used his Mahiki to fool the pair into following and attacking each other in the Canyon of Unending Whispers.
Later, the two assaulted the Toa Metru's Vahki Transport, but Onewa used his Mask of Mind Control to make Krekka attack Nidhiki. The pair fell off the transport and Nidhiki was caught by Shadow Hand, together with Krekka and Nivawk. Teridax absorbed their essences, killing them, in order to fuel his own transformation.
He soon met Roodaka, a Vortixx who wanted the training of a Dark Hunter, but did not want to join the organization. He offered to train her if she would help him escape the island and the organization. Roodaka agreed, but reported his treachery to the Shadowed One. In exchange for training, Roodaka used her Rhotuka power to mutate Nidhiki into a monstrous, insectoid form. The beach where this occurred was later named Nidhiki Beach.
Some time after being mutated, Nidhiki was hired with Krekka to guard the Kanohi Avohkii on Destral. When the mask was stolen by the Toa Hagah, four of the Hagah were later captured. Nidhiki was on his way to question them, but the Toa (now mutated into Rahaga by Roodaka) were freed by Norik and Iruini, who were then also mutated into Rahaga.
This is how Nidhiki looked like after he became a dark hunter.
Note: I built this guy just for fun, I wanted to use the toa metru body desighn, so he would look more like Toa Lhikan. I hope you fellow mocers like this one. :)