During the Core War, Metus, as any other member of the Ice Tribe, served under the Element Lord of Ice. After the Shattering, Metus, with a part of the Ice Tribe which had be stranded on Bara Magna, settled in the White Quartz Mountains. He worked as a trader, Glatorian recruiter, and Glatorian trainer. Metus set out of his village and searched over Bara Magna for a Glatorian who could fight and win in the Arena Magna matches on the behalf of his tribe.
At one point, he and a caravan of Ice Tribe warriors and Agori heading toward an army outpost were ambushed by a group of Baterra, who killed everyone except Metus. While the others were being slaughtered, he escaped on a wagon. Arriving at the outpost, he gave the explanation that he was knocked unconscious and rolled under a wagon, which they accepted. However, Metus then figured out that he had survived because the Baterra only attack those carrying a weapon, which he hadn't.
Shortly before the arrival of Mata Nui on Bara Magna, Metus betrayed the villages, having decided that it would suit him to unite the Skrall and Bone Hunter tribes, acting as a go-between for the two groups and providing them with information on the other villages.
At one point, Tuma requested Metus meet with him. During the meeting, he was told that the attack on Atero would take place the following day. Metus sarcastically asked what changed the plans, Tuma realizing that Metus had information on the Baterra. The two then reached an agreement, and began planning.
He later noticed Stronius and Tuma being attacked by Baterra, the two of them having been knocked out. Unarmed, he ran to the site of the battle and removed their weapons. After the duo woke up, Metus spoke to the Baterra, telling them to leave. They did so, and the Skrall leader demanded to know what happened. It was then that Metus once again bargained with Tuma, giving him the information he desired in exchange for leadership of the Skrall should Tuma be killed or unfit to lead.
When Mata Nui, inside the Ignika, landed on Bara Magna, he created a body for himself and, with the help of his new Scarabax shield, he defeated a Vorox. Metus was traveling with Thornatus when he stopped at the site and witnessed the event. Metus took him to the village of Vulcanus where the fight between Strakk and Ackar was taking place. After Mata Nui saved Ackar from losing the battle, Metus offered him to become the new Glatorian leader but Mata Nui turned down and Metus fled.
Mata Nui later found out about Metus's treachery and used the Ignika to turn Metus into a serpent. He later attempted to kill Mata Nui, Vastus, Ackar, and Kiina, but his plan was thwarted by Click and other Scarabax.
Sometime around the battle of Mata Nui and Teridax, Metus developed the Dreaming Plague. He soon made contact with Sahmad and Telluris, and told them of his condition. Later, the three of them set of to try and find the cause of the disease but were dragged underground by a mysterious tentacle.
In an Illusion, Metus, along with Sahmad, were recovered by other Agori. The Agori and Matoran even used the Ignika to turn him back into an Agori, but it did not help and Metus died.
After Sahmad had recovered from this vision, he, along with Telluris, found him. At this point, Mata Nui's transformation had worn off somehow, and Metus transformed from a snake to an Agori. They then tried to run to the surface from the healing chamber they were in, and found the surface only to find that Annona, the being they had tried to escape from was on the surface too.
Annona, sensing her next meal, took off, but Telluris, Sahmad, and Metus were able to catch up to her before she could. Metus then found himself drowning in an ocean, Aqua Magna. They found themselves near a cliffside, with a fortress positioned on the cliff. Climbing up the cliff, they saw a bunch of Skakdi warriors outside, slashing thin air, since they were trapped in illusions.
A golden being then came out of the fortress. Annona told it that she wanted to feast on the dreams of everyone there. The golden being then began their fight by creating spikes beneath her.
During the battle, Metus watched as the golden being brought the dreams of the Skakdi to life, along with the death of Telluris. Sahmad then noticed a way he could attack Annona, and he and Metus hurried to the site of the rock spikes the gold being created. While Sahmad charged forward to attack Annona, Metus escaped.
Still traumatized by his transformation, Metus had begun a period of reflecting on his past failures and is considering his possible resources in the future.