The Huntsmen (not to be confused with Eric the Huntsman) are the private, elite army of Freya the Ice Queen. They are deadly warriors, trained in combat since childhood and completely loyal to Freya, serving both as her bodyguards, raiders and companions.
Freya formed the Huntsmen shortly after the death of her infant daughter at the hands of her lover, the Duke of Blackwood, an event that saw Freya's powers awaken and proved to be extremely traumatic for her. Freya swore to harden her heart against love and sought to conquer the North. She already had a small army at her disposal, but desired to raise a more elite army who would never abandon her, with the narrator of The Huntsman: Winter's War stating that Freya saw the Huntsmen as a replacement of sorts for the child she had lost. Freya had the soldiers already in her service raid villages and capture the children, who were then trained as warriors. These became the first generation of Huntsmen. With the Huntsmen, Freya was able to carve out a kingdom in the North and struck fear into the hearts of her enemies.
The greatest of Freya's Huntsmen were Eric and Sara, who were among the first children to become Huntsmen. However, after Eric and Sara broke Freya's law against falling in love, Freya tricked Eric into believing Sara had been killed by her fellow Huntsmen, whilst Sara was duped into believing Eric had abandoned her. Eric fled, whilst Sara remained and became Freya's new favourite. However, even she rebelled after being reunited with Eric years later and discovering he still loved her. Eric persuaded the other Huntsmen to turn on Freya. This prompted Ravenna, Freya's sister, to attack them, resulting in the deaths of several Huntsmen; however, Freya stopped her sister from killing the Huntsmen. Eric and Sara, with Freya's help, were able to defeat Ravenna, after which Freya died from injuries sustained in the battle. This freed the remaining Huntsmen and the children captured to be indoctrinated and trained; with their leader dead, it can be assumed the Huntsmen have officially disbanded.
Children recruited as Huntsmen are subjected to a grueling training regime, where they train in various forms of combat, including swordplay, hand-to-hand and archery. In addition to combat training, the Huntsmen are also indoctrinated into Freya's beliefs and rules; namely, to harden themselves against love, to be undyingly loyal to their queen and that they are in fact "lucky" that Freya has chosen them, thus 'sparing' them from the pain Freya experienced.