Hydraxon was originally a member of the Order of Mata Nui and the jailer of the Pit. After his death, the Ignika used its power to transform Dekar into an exact copy of the original Hydraxon, complete with his former memories and no awareness that he had ever been killed or been another person.2
Notes
The original Hydraxon, jailer of the Pit, died in an earthquake over 1,000 years ago. The power of the Mask of Life transformed the Matoran Dekar into a new Hydraxon. He was a relentless tracker and skilled weapons-master. The new Hydraxon's weapons were explosive boomerangs, wrist knives, and a Cordak blaster. The new Hydraxon had all the memories and skills of the old one but did not remember that he was ever Dekar.1
The second Hydraxon used a variety of weapons, including razor-edged explosive boomerangs, wrist knives, and a Cordak blaster.2
The original Hydraxon was a member of the Order of Mata Nui, the jailer of the Pit, and the trainer of the Toa Mata. When the Mask of Life needed a new warrior, it transformed the Matoran Dekar into a duplicate of Hydraxon. This new Hydraxon had the memories of the old one and had no idea that he was once a Matoran. Hydraxon was armed with a Cordak blaster, back blades, wrist blades, and explosive boomerangs.3
The original Hydraxon was revived on the Red Star after his death. This means that there were two Hydraxons living at the same time: one on the Red Star, and one in the Pit.4
The jailer of the Pit was an Order of Mata Nui member.5
Hydraxon was a weapons expert.6
Hydraxon was a living being and was not a robot.7
Hydraxon's species was not seen prior to story year 2007.8
Hydraxon didn't have any involvement with the construction of Order of Mata Nui members' weapons.9
Hydraxon was not a member of the Hand of Artakha.10
Hydraxon didn't have mask powers.11
Hydraxon didn't wear a mask.12, 13, 14, 15
Hydraxon had no mask, that was his face.16
Hydraxon was the first and only jailer of the Pit.17
Hydraxon did his duty. It wasn't a question of whether he liked or disliked it, he did what he had to because it was important.18
Other Information
Greg once said that Hydraxon was never a member of the Hand of Artakha, but this was later contradicted.19