Cahir Mawr Dyffryn aep Ceallach

"His eyes flashed under his winged helmet. Fire gleamed from his sword's blade."

Cahir Mawr Dyffryn aep Ceallach, or simply Cahir, was an intelligence officer of the Nilfgaardian Empire who hailed from Vicovaro. He was the son of Ceallach and Mawr, the brother of Dheran, Aillil and grandnephew to Assire var Anahid.

Early life
He was born to noble Vicovarian pair, Seneschal Ceallach Dyffryn aep Gruffyd and his wife Mawr, in the family's stronghold, Darn Dyffra. He also had a lot of siblings, notably brothers Dheran, Aillil, and three sisters. Among the mages, he was related to Assire var Anahid, his great-aunt.

At some point in his life his skills were recognized by Nilfgaardian Intelligence, maybe thanks to his father's position at court, and he joined its ranks later becoming an officer. He was also given the title of count.

Mission to find Ciri
When the First Northern War started, he was given a secret mission to locate, capture, and bring Princess Cirilla of Cintra back to Nilfgaard. He got very close during the Slaughter of Cintra yet Ciri evaded and fled from him. However, this left a strong impression on Ciri's memories, causing her endless nightmares of the "knight with the winged helmet".

When the witcher Geralt first met Cahir, the latter had recently been released from two years in prison due to the fact that he failed in his mission to capture Ciri and had only expected to escape via the gallows, but the emperor decided to give him one more chance to find and bring him Ciri. If he failed once more though, the executioner's axe awaited him. He also knew that the chance of a pardon was extremely small and forgiveness was non-existent.

He was then sent to Thanedd Island along with Rience and a Scoia'tael commando led by Isengrim Faoiltiarna and where he had the perfect occasion to fulfill the Emperor's will, having the girl right before him without any way to escape. However, when the coup started, she disappeared in the chaos but eventually he found her as she ran to escape the tower. Ciri evaded him once more though when she jumped out of a window and landed safely on the narrow bridge far below. Despite this, some of the Scoia'tael found a saddled horse and Cahir took off after the princess and eventually cornered her in a courtyard. As he moved in to take her, Ciri's training at Kaer Morhen suddenly kicked in and she attacked, moving too fast for Cahir to stop her, giving him a permanent injury to his hand in the process. She ultimately defeated him but, on seeing there was an actual face behind the winged helmet, she let him live.

After being spared by Ciri, some of the elves found him while he was bleeding out but before they could help him Geralt attacked and killed all the elves. As he moved to kill Cahir, the one who'd haunted Ciri's dreams, the witcher asked the knight why he should spare him. Cahir answered that he was the reason Ciri survived the Slaughter of Cintra, having rescued her from the fires. When Cahir opened his eyes again, the witcher was gone.

He then tried to head to Tor Lara tower, but when the tower exploded he was knocked unconscious and his body was found by Isengrim. Knowing the approaching royal troops couldn't get their hands on the Nilfgaardian as it'd be proof of the Empire's involvement, the elf took him back to the ship they'd come on and sailed away. After they landed in a safe location, Cahir began to rave about Ciri, Geralt, and the Tower of Gulls before demanding they return him to the island, but Isengrim believed he'd gone mad and refused as the war had already started.

By order of Emhyr and Vattier de Rideaux, an arrest warrant was put out on Cahir for providing a false Ciri (though he had nothing to do with this) and not returning to Nilfgaard for his failure. Several weeks later, the news reached Isengrim and Cahir let himself be tied up without resistance and placed inside a coffin. Isengrim then had two Hav'caarens deliver him to the designated location where Nilfgaardian commandos were to then take him back to the Empire and punish him for treason.

Traveling with Geralt
As fate would have it, while the Nilfgaardians and the Hav'careens were resolving the deal, Geralt and Dandelion were in the surroundings. When a fight erupted between the smugglers and the Nilfgaardians, Geralt and Dandelion, with the help of Milva, killed all of them and then opened the coffin finding, to their great surprise, Cahir tied and muzzled. Once again Geralt spared the black knight, leaving him a knife to free himself, but not before he recommended that if he ever saw him again, he would kill him once and for all before the group left as they could hear an army approaching. Cahir then freed himself, grabbed one of the now dead soldier's horses, and escaped before the army found him.

Despite Geralt's warning, Cahir took off after the group, though he never directly approached them. It was only several days later when the group, fed up with knowing someone was following them but not sure who, confronted them only to find Cahir once again in their presence, this time riding a chestnut colt. As Geralt demanded Cahir fight him, Cahir stated he didn't wish to fight but to join them in rescuing Ciri. Geralt strongly objected to this, threatening to kill him once more but Cahir, unwillingly to pull out his weapon like Geralt demanded, reiterated that he didn't want to fight, leaving the two in a stalemate. Only when Milva stated she could put an arrow in his horse to prevent Cahir from catching up with them as they continued on did Cahir mount and run off.However, he continued to follow the party at a distance, even after they joined Zoltan Chivay's company. The dwarf though could also sense they were being followed, which became clear one day when their group attacked some raiders on a farm. A lone raider had managed to escape into the woods to alert the main force, but suddenly let out a scream before going silent as Cahir, hidden nearby, had taken him out. However, a few days later it appeared he was no longer following them as the company was passed by a riderless chestnut colt with no sign of Cahir.

It turned out he'd been ambushed by three brigands, resulting in his horse running off and by the time he got a new mount, he'd fallen far behind the group. Knowing they'd go east, he headed that way and finally caught up with Geralt's group just as they reached a refugee camp on the Chotla river. However, shortly after the camp was overrun by troops, sending the refugees fleeing and grabbing any available horses. Wanting to help, he rode after those who'd stolen the group's horses and helped out Milva as she was knocked to the ground, fending off the peasants before returning one of her arrows. After an initially tense moment, the two gathered up the rest of the horses and hid in the forests nearby, with Cahir telling her how he'd ended up in the coffin before revealing that Ciri wasn't in Nilfgaard like Geralt thought. Once it was nightfall, the two went to investigate the camp but on seeing no fires, realized everyone was gone, either having escaped, killed off, or taken captive. However, Regis suddenly appeared and once Milva reassured Cahir that he was a comrade, Regis informed them that they needed to get to Fort Armeria quickly, as Geralt and Dandelion were in trouble and had them wait at a designated spot.

Geralt's company
As they waited, Milva and Cahir continued to discuss Ciri, with the knight revealing he'd met Ciri for the first time three years ago during the Slaughter of Cintra and had gotten her out of the city. Geralt soon arrived with an injured Dandelion but held off from saying anything to Cahir due to the bard's wounds. As Regis appeared and bandaged him up, Geralt, who now knew Regis was a vampire, drew a sword on him but ultimately let him go. However, when Geralt then turned his attention on Cahir, intending to kill him or also send him away, Milva defended the knight, stating he saved her life and helped get the horses back and if Geralt made him leave then the witcher was on his own as she'd refuse to continue traveling with him. So, with reluctance, Geralt let Cahir travel with them.

Later that day they found a small island to rest on and Geralt talked in private with Cahir, believing initially that Cahir just wanted to re-capture Ciri to save himself from the gallows, yet couldn't understand why he was still holding back from killing the knight. Cahir then revealed he just wanted to rescue Ciri and, like Geralt, had dreams of what she was doing with the Rats. Despite this, Geralt thought he was just repeating what he'd told Milva until Cahir revealed a dream that Geralt hadn't told anyone else, being too afraid to mention aloud what Ciri had done in it. Afterwards, Cahir went off to capture some fish for dinner, returning with a sizable pike to add to the group's soup.

With Cahir's news that Ciri wasn't in Nilfgaard like they previously thought, the group then decided to head to Caed Dhu, a druids' circle, to learn more.

During the assault on Stygga, he faced Leo Bonhart. Ciri told Bonhart that he was the witcher, but the seasoned killer was not frightened by this bluff and defeated the "Black Knight" with relative ease. Though he seemed an enemy at the outset, his sacrifice gave Ciri and Angoulême time to escape.

He loved Ciri and had frequent dreams about her where he saw her as an adult with a rose tattoo on her thigh.

Trivia

 * Cahir's mother's name Mawr means "big" in Welsh. His father's name, Ceallach, is of Irish-Gaelic origins, and means "bright-headed".