Introduced as initially a side character in 'Before They are Hanged', Caul Shivers was a young Named Northman that originally sided with Bethod. Having heard that Dogman and his crew had Rudd Threetrees as their Chief, he and his two score of Carls join with them and the Union to fight against Bethod. He and many of the men under him seemed disillusioned by Bethod's campaign to regain Angland from the Union as well as his dealings with the Shanka and far flung Cinna troops. In the incurring battle, he helped fight against the Feared and subsequently was one of the supportive voices to make Dogman Chief of their band.
In 'The Last Argument of Kings' it is learned upon Logen Ninefingers returning to the North to fight for the Union that Shiver's brother was murdered by the Bloody Nine after he had promised mercy; cutting off the defeated limbs and nailing his head to Bethod's standard. Shivers' tells Logen that this broke his father, Rattleneck and it drove him to an early grave due to drink and grief. He firmly blames Logen for what happend to his family, but overcomes his want for vengeance by standing with the Dogman and the Union in the subsequent battles following in the High Places where they hold up in the mountains to draw Bethod's armies into the North. When Logen faces the Circle with Fenris the Feared he is one of the men holding a shield for him.
After Logen is proclaimed King of the Northmen when he defeats Bethod by challenge in Carleon, Shivers accompanies him and the Dogman to Adua to fight for the Union against the Gurkish invasion. Upon returning to the North after the successful battle to secure the Union, he is confronted with the chance to get revenge for his brother's death when Black Dow betrays Ninefingers, but hesitates and decides that he won't do Black Dow's dirty work for him and that he's better than both of them for their petty fighting.
Best Served Cold
Shivers is a main POV character introduced as a newcomer to Styria via Westport with a wish to be a better man and find honest work that doesn't involve endless battles. Spurred on by tales from a merchant about the niceness of Styria, he has high expectations that he'll be able to find himself a niche, but encounters prejudice and problems from the onset, resorting to begging and taking odd jobs to barely keep his head above water. He is subsequently rescued by Monza Murcatto when four bandits attempt to steal the last of his belongings and she offers him a job to take a message to a man in a tavern. Deciding that he needs the money, he takes her job and the knife she offers.
He joins in Monza's quest for vengeance against Duke Orso, deciding that the money and cause were worth the killing. On the second mission in Westport to kill the banker, Mauthis, he becomes intimate with Monza and they enter into a somewhat casual sexual/romantic relationship.
In Sipani, Shivers' is roped into staging a recreation of the Circle fight that Logen fought against the Feared for the patrons of the Prince Ario's party at the brothel. He hires another Northmen to play as the Feared and himself as Ninefingers much to his ironic dismay. During his 'fake' duel, the hired Northman, Greylock decides to kill him as revenge for the death of his younger brother years prior who was had been standing guard along the docks near Uffrith and was killed when the Union took over the town. Shivers' manages to kill Greylock as a fire breaks out in the pleasure house and he is forced to save Monza and they both flee the burning brothel.
After the death of Orso's son, Prince Ario, Monza and the band go to Visserine, where they are planning on disguising themselves as Talins' soldiers to get closer to General Ganmark. This doesn't go to plan as they are turned in as spies and Monza and Shivers are locked up in the dungeons of Duke Salier's palace. During a session of torture to glean information from them about Orso's plans, Shivers' right eye is damaged with a red hot poker; leaving a permanent gaping wound where his eye was and a melted scar down the side of his face. While he is healing in Visserine (now under the protection of Duke Salier) he murmurs that it should have been Monza that suffered this fate as it was her revenge that landed them there in the first place; he was only going on to help.
This experience somewhat dulls the previous optimism Shivers' has that he can be a better man, deciding that Monza's words mercy and cowardice are the same are true and that good men die just like bad men and there is no difference between the two.
When Monza decides to join Duke Rogont, head of the League of Eight, in Ospria he becomes drunkenly disillusioned and jealous over perceived slights by Monza in favour of the Duke at a dinner party held in honour of Monza's joining as his General. He meets Carlot dan Eider who further incites his anger towards Monza by telling him more about her past although he denies it and tries to make it out as though Carlot is only interested in getting revenge.
During the battle of Ospiria he saves Monza's life after she leads a charge into the valley against the Talins' army led by Prince Foscar. After the Talins' defeat, Shivers, having gone off the deep end in terms of morality, kills Prince Foscar rather brutally when Monza hesitates; about to show him mercy to the younger man and solidifies his conscious decision to throw away his previous held beliefs. When Monza asks him why he did it, he tells her that it's what she wanted. During these events, he eventually secures a metal eye to replace his lost one and begins to wear it throughout the rest of the book.
Later after a victory of the Talins' army in Ospiria, he is seduced by Carlot dan Eider and she proposes that he put down Monza when the time is right for her employers back in the Union who wish Duke Orso to succeed. Shivers considers her proposition and seems to be undecided about whether or not to go through with it.
However, in the final arc of Monza's revenge scheme to finally kill Orso himself, Shivers having accompanied Monza to Talins turns on her in the heat of battle and tries to kill her; stopped only by Friendly who intervenes. Friendly and Shivers engage in a close battle until they are interrupted by Shenkt who disarms and incapacitates both of them. Shivers fate seems undecided as he's placed into custody in a dungeon in Talins' but Monza decides to grant him mercy, showing that she had changed her view on her own motto and would let him go. There is some question as to whether or not the child Monza is carrying is Shivers' or Duke Rognot, but at the close of the book, it seems as though he has no knowledge of it.
Shiver's has returned to the north to work under Black Dow as a man who 'takes cares of things;'. He is frequently used as Dow's muscle and seems to have taken to speaking lowly and hoarsely to cultivate a terrifying reputation somewhat similar to Logen had as the Bloody Nine. In the end, Shivers' becomes disenchanted of Black Dow's treatment of him and stands in as challenger for Calder, son of Bethod where he subsequently kills Black Dow.
Shivers returns in Red Country as a main character a question of whether or not he can actually forgive and change comes to the fore.
Described as very tall and broad through the shoulders, Shivers has long dark hair that was cut once in Best Server Cold to fit in better with Styrian fashion. He also sports a permanent scar extending from the lower half of his face upwards to his brow from where his eye was burnt out and has replaced it with a metal one. During the course of The Heroes, he is noted as having a low, hoarse voice and rarely smiles when he’s not in battle. His weapon of choice is an axe.
Family Brother - A Named warrior who fought against the Bloody Nine and lost. His limbs were cut off and his head nailed to Bethod's standard. It is revealed in Best Served Cold that on the outside he seemed like a generous and caring old brother but would secretly bully and beat up Shivers through most of his life until his death. Although he blames Logen for his brother's death, Shivers is unsure whether or not he's grateful that Logen killed him or just angry that he took away the satisfaction of doing the deed himself.
Rattleneck (Father) - A Named warrior who by all accounts was a rather fair man who valued the old ways and was very proud of his firstborn, Shiver's older brother. When his son died, he took to drinking and drove himself to an early grave. He was belligerent and unkind to Shivers and frequently told him that it should have been him that was taken back 'to the mud', not his older brother.