Confusingly, many works have two wounded Grail Kings who live in the same castle, a father and son (or grandfather and grandson). The more seriously wounded father stays in the castle, sustained by the Grail alone, while the more active son can meet with guests and go fishing. For clarity in the remainder of this article, where both appear the father will be called the Wounded King, the son the Fisher King.

The Fisher King appears first in Chrétien de Troyes' Perceval, but the character's roots may lie in Celtic mythology. He may be derived more or less directly from the figure of Bran the Blessed in the Mabinogion; in the Second Branch, Bran had a cauldron that could resurrect the dead (albeit imperfectly; those thus revived could not speak after they were resurrected), which he gave to the king of Ireland as a wedding gift for him and his sister Branwen. Later, he wages war on the Irish and is wounded in the foot or leg, and the cauldron is destroyed. He asks his followers to sever his head and take it back to Britain, and his head continues talking and keeps them company on their trip. The group lands in Grassholm, where they spend 80 years in a castle of joy and abundance, but finally they leave and bury Bran's head in London. This story has analogues in two other important Welsh texts: the Mabinogion tale Culhwch and Olwen, in which King Arthur's men must travel to Ireland to retrieve a magical cauldron, and the obscure poem The Spoils of Annwn, which speaks of a similar mystical cauldron sought by Arthur in the otherworldly land of Annwn.

In the Welsh Romance Peredur son of Efrawg, based on Chrétien (or derived from a common original) but containing several prominent deviations, the Grail has been removed. The character of the Fisher King appears (though he is not called such) and presents Peredur with a severed head on a platter. Peredur later learns he was related to that king, and that the severed head was that of his cousin, whose death he must avenge.

The Fisher King's next development occurs in Robert de Boron's Joseph d'Arimathie about the end of the 12th century, the first work to connect the Grail with Jesus. Here, the "Rich Fisher" is called Bron, a name similar enough to Bran to suggest a relationship, and he is said to be the brother-in-law of Joseph of Arimathea, who had used the Grail to catch Christ's blood before laying him in the tomb. Joseph founds a religious community that travels eventually to Britain, and he entrusts the Grail to Bron. Bron, called the "Rich Fisher" because he catches a fish eaten at the Grail table, founds the line of Grail keepers that eventually includes Perceval.

In the Didot-Perceval, thought to be a prosification of a lost work by Robert de Boron, Bron is called the "Fisher King", and his story is told when Percival returns to his castle and asks the healing question.

Wolfram von Eschenbach takes up Chrétien's story and expands it greatly in his epic Parzival. He reworks the nature of the Grail and the community that surrounds it, and gives names to characters Chrétien left nameless (the Wounded King is Titurel and the Fisher King is Anfortas).

The Lancelot-Grail cycle includes a more elaborate backstory for the Fisher King. Many in his line are wounded for their failings, and the only two that survive to Arthur's day are the Wounded King, called Pellam or Pellehan, and the Fisher King, Pelles. Pelles engineers the birth of Galahad by tricking Lancelot into bed with his daughter Elaine, and it is prophesied that Galahad will achieve the Grail and heal the Wasteland. In the Post-Vulgate Cycle and Malory's Le Morte d'Arthur, the Fisher King's wound was given to him by Sir Balin in the "Dolorous Stroke". To defend himself from an enraged Pellam, Balin grabs a spear and stabs him. The spear is the Spear of Longinus, however, and Pellam and his land must suffer for its misuse until the coming of Galahad.

In Malory's Le Morte d'Arthur, there are four characters (some of whom can probably be identified with each other) filling the role of Fisher King or Wounded King:

It would appear that Malory intended to have one Maimed King, wounded by Balin and suffering until healed by his grandson Galahad, but never managed to successfully reconcile his sources.

King Pelles is the name of the Maimed King in some versions of the Arthurian legend. One of a line of Grail keepers established by Joseph of Arimathea, Pelles is the father of Eliazer and Elaine, mother of Galahad, and resides in the castle of Corbinec in Listenois. Pelles and his relative Pellehan appear in both the Vulgate (Lancelot-Grail) and Post-Vulgate Cycles, as well as in later works, such as Malory's Le Morte d'Arthur (in which Pellehan is called Pellam). In the Vulgate, Pelles is the son of Pellehan, but the Post-Vulgate is less clear about their relationship. It is even murkier in Malory's work: one passage explicitly identifies them (book XVIII, chapter 5), though this is contradicted elsewhere.