Thorn is a jaded warrior that like many members of her tribe was cursed with a diseases known as Stoneflesh caused her skin to harden into rough protrusions.
Thorn is the younger sister of Stag. Both were born with abnormally aggressive cases of Stone Skin, although while Stag's quickly covered most of his body, Thorn's was mostly confined to her face and arms. Upon becoming a teenager her hands began to weld together into inarticulate clubs. Enraged by her fate, she sharpened her forearms into spears and set out on a quest with her brother to find a cure before transforming even farther.
The two eventually found miracle healer, but soon found that he could only cure the sick by absorbing the affliction into himself. Thorn refused to allow the man to take on their pain, and although Thorn was frustrated she reluctantly agreed. So they continued their quest, hoping to find a cure somewhere else.
Thorn and Stag then went to investigate a nearby village that was told be be suffering a similar condition. When they went to see if the stories were true, they were attacked by fearful villagers who believed them to be infected. In reality, the local disease known as Bloodspur was quite different. It could be spread by blood to blood contact, and exhibited signs of mania and madness in addition to an alarming healing factor that would eventually transform the infected into unrecognizable tangles of spikes.
One of the medical officers was quick to realize there was something different about the siblings, and rescued them from being sent to the skewer pit were the infected were disposed. He held them until he was confident they were of no threat to the others, around which point the Wanderers came into the town in hopes of providing aid. They were unable to create anything to combat Stoneflesh, but Thorn and Stag agreed to join the Wanderers in hopes of coming across a new solution.
Thorn made an effort to keep a distance from the team, preferring to stay alone or with Stag. Eventually she became aware of the mutual attraction between her brother and Pearl. Thorn was highly resentful of Pearl for her sheltered life and nauseating naivety. She even tried to convince Stag to leave the group, but he refused.
Stag soon took a turn for the worse, and it became obvious they would not find a cure in time. He told Thorn not to be upset, but soon became unable to speak. The others excused themselves, but Thorn asked that Pearl stay. The three sat together in silence the whole night. As they left in the morning Pearl began to saw something to Thorn, but she interrupted her by simply saying that she knew.
Thorn became more closed off as she mourned the death of her brother, and eventually decided to leave the group. Having failed to save her brother, she no longer had a need to search for a cure. She also knew that Stag although he never said it, he hated being a burden on her and would have wanted her to live her own life. So she said her good byes to the group and left to find her own path.
She eventually went back to the region affected by Bloodspur and found the disease had become much worse. The effects spread much quicker, and those affected quickly became animalistic and violent. The only way to kill them was to sever the spine, particularly through decapitation. This was usually only possible in the early stages, as their skin would quickly become too tough to penetrate. Thorn's own condition making her immune to the infection made her an essential tool in protecting those remaining from the infected.
Thorn is highly resistant to damage in the areas afflicted by Stoneflesh, but even her regular skin has the durability of rough hide. The nerve endings in her hardened skin are also dead, meaning she does not feel pain from superficial blows. She has mastered using her sharpened arms as weapons, although she is incapable of manipulating traditional tools without hands.
Unlike her brother, the hardships Thorn has faced in her life have left her bitter and angry at the world. She is often hostile and flippant to those around her, and is quick to assert dominance to anyone she feels has disrespected her. She is however king and nurturing towards her older brother.