The Bone Hunters, during the Core War, were misfits. They had no organized tribe. No Elemental Lord. They were on their own for the most part. Organization came under a wise soldier named Cruor, who led his fellow tribe members into battle wherever they could. They would even raid harmless Agori camps.
The Lords all but ignored them, and told their armies to do the same. Cruor was able to raise a powerful fighting force, and tried to hire their forces out as mercenaries to the Lords who wanted their numbers and strength. The Lords saw this as an outrage, but only one did anything.
The Elemental Lord of Sand was tired of them, and when he caught wind of the Elemental Lord of Rock trying to have some of his Skrall make an alliance, he sent his Vorox soldiers out to deal with the nomads.
The Bone Hunters were all ambushed, and butchered. Their swords weren't fast enough. They couldn't use any scavenged weaponry with enough proficiency or fast enough, and were butchered.
Cruor, in the confusion, was attacked, and his eye taken out. His body was battered, and he was left for dead. His members managed to hold off the Vorox long enough for the officers to escape with Cruor, and for the rest to flee afterwards.
Cruor's armor was patched as best as they could, and they were kept with only their basic weapons, and steeds. When the Shattering struck, the Core War survivors began to forge life for themselves. The Bone Hunters, under Cruor, saw their opportunity. They were going to be bandits and marauders.
Many years later, Fero would challenge three Glatorian-Strakk, Tarix and Gresh-as they protected Berix. Strakk managed to wound Skirmix, Fero's steed. The other two managed to repel Fero, and force him to flee.
Later, the three Glatorian and Metus would be ambushed by multiple Bone Hunters, and be captured and taken back to their camp. They managed to flee when a group of Vorox attacked under Malum's orders, and escape.
Later a Bone Hunter of that group would meet with Tuma, and get some plans for the attack on Vulcanus. Strakk cleaved him in half, and found the plans on his way to Roxtus with the other two Glatorian.
Later, Vorox would butcher a section of that group, again, under Malum's orders.
Fero would then lead a raid on Vulcanus with the new information. A group of Glatorian managed to defeat and repel them.
Later, Fero would be on trial from Cruor. To redeem himself, he would attack Vulcanus again during a sandstorm. He was with two other officers-Letum and Nequam. Letum would be killed in the battle with other Bone Hunters, but the raid would be mostly successful. Malum arrived and helped Vulcanus to defeat the Bone Hunters, forcing them to flee.
Later Bone Hunters would attack Tesara with Nequam leading them. They would be repelled by Gresh, Vastus, and Strakk.
Later, Vastus would lead a team to the Bone Hunters camp, trying to wipe them out. A few were killed by sneak attacks, but the main camp was on alert. Nequam was killed by Vastus's scythe, and Fero was killed when Mata Nui unleashed the power of the Ignika over himself. Cruor managed to buy enough time to flee with a battalion of Bone Hunters and get away safely.
During the Grand Tournament, Tuma had the Bone Hunters attack the group that Raanu traveled with, attempting to use him as their assassin to murder the group. They blasted the Glatorian around with their Thornax Launchers, and keep them all on the run. When Raanu was fleeing for his life after he betrayed the team, a group came to save him, but they were all butchered by Mata Nui's powers.
Cruor reorganized the rest of the Bone Hunters, and fled when Tuma's army pulled away from Atero.
Eventually, the Bone Hunters found their way to the Holy Spherus Magna Empire, and came under their leadership. Cruor, under Invado's orders, attacked Bara Magna with his men, going after Vulcanus to destroy the vehicle fleet that it held. After some time, the Bone Hunters were defeated by the vehicle armada with a sizeable death toll for their side, but the escape of Cruor.