Kai is a female character who features in BIONICLE (Generation 1).
Legends of Metru Nui
1001 years ago, Kai lived and worked in the district of Ga-Metru with her fellow Ga-Matoran on Metru Nui. This changed when all the Matoran of Metru Nui (including Kai) were rounded up by Vahki under the control of Makuta Teridax and placed into stasis in Matoran Spheres as part of Teridax's plan to replace Mata Nui as their ruler. However, Teridax was defeated by the Toa Metru before he could reawaken the Matoran (BIONICLE 2: Legends of Metru Nui) and the the Matoran Spheres were recovered and transported to the island of Mata Nui. The Toa Metru then sacrificed their Toa powers to awaken the Matoran, but because the Matoran (including Kai) had been in stasis for so long, the Matoran Spheres had shrunk their bodies into smaller, less powerful forms and had erased all memories of their lives on Metru Nui. (BIONICLE 3: Web of Shadows, et al.) Kai settled into her new life on Mata Nui and became an avid sailor. (Mata Nui Online Game II: The Final Chronicle)
Island of Mata Nui
Around 500 years later, Kai built a large canoe and started a rowing club in Ga-Koro that Macku, Marka, and Amaya joined. On their first trip out to sea in the canoe, Kai and her teammates were attacked by a Great Temple Squid and Marka was dragged into the sea by one of its tentacles. The remaining Ga-Matoran fearlessly jumped into the water after Marka and beat the Rahi's eye with their oars until it released her. The Rahi appeared to retreat, but Kai noticed that it had merely changed course and was headed for Ga-Koro instead, so she rallied her teammates and swam after it. The Great Temple Squid was eventually defeated by Amaya, who stayed underwater much longer than her teammates to restrain its tentacles with rope, hindering its movement until it left out of frustration. (Tentacles by Turakii #1 Lavasurfer)
After the Toa Mata had arrived on the island, an Teridax-controlled Tarakava attacked Ga-Koro and forced all of its Ga-Matoran (save for Macku) into one hut. The Tarakava then damaged the hut's floatation system, causing it to sink beneath the waves. The trapped Ga-Matoran (Kai included) were saved when Takua repaired the flotation system and the hut returned to its former position. (Mata Nui Online Game)
Later that year, the Turaga announced the Rebuilding, an event in which all the Matoran of Mata Nui would be rebuilt into larger, stronger forms. This was to compensate for the strength that the Matoran had lost to the Matoran Spheres a thousand years prior. Like all the other Matoran on the island, Kai was rebuilt into a stronger form. (Wall of History) By this time, Kai had occupied herself by using flax to make string and rope for the village. Because Kai needed 5 flax for each string, Hahli traded 50 flax for 10 strings so that she could obtain a net from Shasa. (Mata Nui Online Game II: The Final Chronicle)
When Hahli and Macku were selected to be Ga-Koro's new Kolhii champions, Kai congratulated Hahli and talked to her about the Kolhii Skill of Speed, which was derived from Ga-Koro's Principle of Purity. Kai gave Hahli an old Speed Charm and coordinates to an area of the sea that contained Takea sharks, because legend claimed that a Takea shark could teach its speed to anyone who caught it. Before Hahli left, Kai added that Pelagia could take Hahli to that area. (Mata Nui Online Game II: The Final Chronicle)
Later still, Kai watched the Kolhii match between Ga-Koro and Onu-Koro and praised Hahli for her performance in it. (Mata Nui Online Game II: The Final Chronicle)
Return to Metru Nui
Later that year, the Turaga revealed the truth about the Matoran's former lives on Metru Nui and announced that they were to return to their former home. The Ga-Matoran (Kai included) aided in the construction of boats for the journey. (BIONICLE Adventures 1: Mystery of Metru Nui) Once the exodus to Metru Nui was complete, Kai helped to repair the damage to the City of Legends (BIONICLE Legends 1: Island of Doom) and continued to live there even after Teridax's eventual takeover of the Matoran Universe. (Official Greg Discussion)
When the Great Spirit Robot was critically damaged in the Battle of Bara Magna, the Matoran of Metru Nui (Kai included) emigrated from the Matoran Universe to Spherus Magna. (Official Greg Discussion)
- Kai has been directly referenced (by name) in only two canon works: Mata Nui Online Game II: The Final Chronicle and Tentacles by Turakii #1 Lavasurfer.
- Mata Nui Online Game II: The Final Chronicle
- Tentacles by Turakii #1 Lavasurfer