Born into a wealthy Skelligan family, the Law of Surprise hit the Clan Tuirseach hard. Cairbre was given up in replacement for her brother, who was slated to become a warrior. Having been taken later, Cairbre has memories of being a Skelligan over being any Bear Witcher.
A backfire studying signs left Cairbre afraid of casting magic and hesitant to use signs. He reacted well to the trials, given extra mutations that would increase his strength and constitution beyond that of a normal witcher's.
Early on the Path, Cairbre took a contract to kill a town mage who had allegedly turned evil. After speaking to Demihaud, the mage, Cairbre realized that the contract was false - Demi was legitimate, the contractor was just unwilling to pay for Demi's services. Cairbre agreed to have Demi hide during the night, move out his things, and then burn the house to the ground the next morning to cover up Demi's alleged death. Demi realized Cairbre's fear of magic after seeing Cairbre light the house with a match and, on the way out of town, confronted Cairbre: agreeing to teach the witcher ways of magic for saving Demi's life from a future mob.
Demi would spend the next decade taking Cairbre under her wing, teaching him the art of magic and helping him work through his fear while Cairbre provided protection for him to find and rejoin the Scoi'atel. Towards the end of their decade together, Demi convinced Cairbre to reconnect with his Skelligan family; when he travelled the isles to see them again, though, they were unable to give him rights to his place in the Tuirseach Clan, as doing so would defy the powerful chaos magic involved in the Law of Surprise that had claimed him as a boy. To support his travels on the Path, they tattooed him with bind rune blessings along his body; personally done by the artist for Clan Tuirseach. Cairbre would wear these as he continued his life in travel, not welcome to stay but protected when he leaves.
One day in his travels, Cairbre happened upon a contract to slay a cursed frog in the belly of Novigrad. Cairbre took it, only to discover that he had been set up by a warring criminal; the cursed frog beast was actually the son of a major Novigradi crime lord named Kalina, who would go on to hunt him for revenge. It was during this time that Cairbre would meet Jola, a mage that he fell in love with. They only had a few months to settle before Kalina killed Jola - revenge for killing the closest loved one to her. This spurred a blood feud that would last forty years - a violent one that took the rest of Kalina's family, shattered Cairbre's knee, and burned Cairbre's original ancestral home in Skellige.
Eventually, Cairbre killed Kalina - and without the fight, found himself incredibly empty. He had hated her for so long, but everyone else he cared for wasn't close to him like she was - leaving him to take on more and more dangerous contracts to try to fill the void that the blood feud had once filled with adrenaline and fear.
During one of these contracts, in his carelessness, Cairbre accidentally detonated one of his bombs too early - horrifically scarring his face. At the request of his mentor, Cairbre took time away from being a witcher to work within the Scoi'atel where Demi would know about his whereabouts, and Cairbre also began to fight with a helmet and shield. It wasn't enough, though, and Cairbre eventually turned back to the Path - where he was poisoned and buried by an Endrega specifically altered with poisons damaging to witchers. It took three days for him to crawl out of where he had been left, and when he was found by the Scoi'atel, he was delirious, and refused sleep. This incident leaves him with nightmares to this day.
- Nowadays, Cairbre paces himself, working between the Path and the Scoi'atel intelligence ranks when one proves too difficult than the other.
- Cairbre is on the hunt for who - or what - is mutating beasts to kill witchers, with little luck.
- He still visits Skellige, on occasion. Anyone who remembers him is long dead, though.
- His age has given him many people he knows, but very many friends.
