Kylma was a Ko-Matoran who worked in Ko-Metru.
Before the Great Cataclysm, Kylma lived and worked in the region of Ko-Metru. When the Matoran were taken away by the Vahki, Kylma was also taken. The Vahki were being commanded by Teridax who was in the form of Turaga Dume. He was put in a Matoran Sphere. Later when the Toa Metru rescued all of the Matoran he was reawakened on the shores of Naho Bay.
Due to the fact that Kylma was in a Matoran Sphere his size and strength was decreased. He also lost all of his memories. In the first years of The Dark Time he worked with all of the other Ko-Matoran on creating the village of Ko-Koro. The village leader would be Turaga Nuju former Toa Metru of Ice. They made the village out of dismantled Airships.
After the Bohrok-Kal were defeated Kylma and the other Matoran were rebuilt into larger, stronger forms like they had been before the effects of the Matoran Spheres.
The Return to Metru Nui
Kylma and the other Matoran built the Boats so the Matoran could return to Metru Nui.
When the Toa Nuva eventually got back to Metru Nui they celebrated Mata Nui's awaking. But Teridax revealed he was in Mata Nui's body and he had control over the Matoran Universe.
The Matoran then scattered then separated to avoid being captured by Teridax. It is unknown what Kylma did until Teridax landed on Bara Magna but, soon after, a shard of one of the moons of Bara Magna struck Teridax on the head and he was killed as a result. The inhabitance of the body came out and Aqua Magna and Bota Magna were joined onto Bara Magna. The world then bloomed with life and the elements returned to the newly reformed Spherus Magna. Mata Nui's unstable robot form plummeted to the ground and all of the worlds inhabitance rushed to the site. All that remained was the Mask of Life.
- Mata Nui Online Game II: The Final Chronicle