Who Is King Pellam (the Maimed King)?
The wounded king struck by the Dolorous Stroke
King Pellam is the king of the castle of Listeneise who received a wound that would not heal for many years from the knight Balin's "Dolorous Stroke." He is the older brother of Garlon, the invisible knight.
In Episode 3, enraged when his brother Garlon is killed at a feast, he chases Balin himself. Having lost his weapon, Balin flees into an inner chamber of the castle, finds a mysterious spear there, and strikes King Pellam with it. With this one blow the castle collapses, and the three surrounding kingdoms are laid waste.
In Malory's original text, it is hinted that this spear is the one that pierced Christ on the cross. Pellam's wound is said not to heal until Galahad cures him during the quest for the Holy Grail, linking him to the "wounded king" of the Grail stories.