The Breton Ankoú is etymologically related to the Cymric Angau though whereas Angau is a personification of death, Ankoú is perceived more as death's helper (for death is a state and not a physical being).

Ankoú is often depicted as being all skin and bones. Though the emaciated Ankou wears a long concealing cloak, has wooden clogs on his feet and his head is covered by a black, wide-rimmed hat bearing a floating ribbon. In his right hand he carries a scythe with an inverse handle. At night he drives a creaking cart and is accompanied by two skeletal footmen. Ankoú's cart is drawn by a sturdy horse which is accompanied by an old skinny beast. This deathly convoy, known as the Karriguel an Ankoú. stretches far into the distance across heaths and sunken lanes. Anyone hearing the deathly entourage approach should quickly take cover, as none who have seen it up close have not lived to tell the tale. The grim Ankoú, powerful Reaper of Souls, assists death in its task.

One legend has it that the Ankoú was once a cruel prince who foolishly challenged Death to a game of chance. The prince, a man prone to fits of jealous anger and petty viciousness loved the hunt above all other pursuits and he craved the instant of his quarry's death almost as much as he craved the suffering of his fellow man. It so happened that one night, on the Sabbath, he urged his companions — who were almost completely drunk — to rouse themselves from the dining table and to join him in some sport. Once their horses were saddled the dogs were loosed and they chased them into the nearby forest. They spied a pure-white stag and gave chase, whereupon they encountered a massive figure, all clothed in black, who rode a milk-white steed. Both man and stag, of course, were from the otherworld and the rider of the pale horse was none other than Death himself. Angry at having found this stranger on his land the prince challenged him to a contest. Whomever took down and killed the stag would not only keep its meat and hide but would also be allowed to determine the fate of the loser. The stranger, whispering in a voice that sounded like the scraping of leaves against a drystone wall, readily assented.

Spurring their steeds the two challengers gave chase to the stag, but the Prince's steed could only manage a few footfalls before the stranger had caught-up with the stag, notched his bow and dispatched the animal with a single shot. Indeed, it was over so quickly that the prince could only look-on, aghast. Unbowed, the prince ordered his men to surround the stranger as he boasted that he would bring two trophies home this evening.

But the stranger merely laughed as he proclaimed: "You can have the stag, foolish man, and with it all the dead of the world. If your joy is to hunt then hunt thou shalt — across battlefield and plague-pit and hearth shall you hunt your trophies. And they will all reek of decay." This is how Death gained a faithful servant, the Ankoú.

Another tale of the Ankoú involves three drunken friends who were making their way home one night. On the road they came across an old man driving a rickety cart. This, of course was the Ankoú. Two of the men started taunting the figure and when they received no reaction they began to throw stones. This caused the cart to swerve so that it slewed into a pothole, breaking the axle. Seeing this the stone-throwers fled the scene. But the third friend felt bad about what had happened and found a stout branch to replace the broken axle. He also gave Ankoú his shoe-laces so that the branch could be affixed to the cart. The next morning the two friends who had thrown stones were found dead, whereas the one who had stopped to help was still alive but his hair had been turned entirely white. For the remainder of his life he never mentioned to anyone what had transpired that night.