Merlin is a wizard from Arthurian legends. The character first was depicted in Historia Regum Britanniae with the name Merlin Ambrosius (Welsh: Myrddin Emrys).
Merlin's back-story traditionally depicts him as being a cambion, meaning he was born of a mortal woman and sired by an incubus. Although his mother's name is barely said, the Prose Brut reveals it is Adhan. When he matures, he engineers the birth of Arthur through magic. Later authors have Merlin as King Arthur's advisor till The Lady of the Lake imprisons him.
Merlin plays a role in the birth of King Arthur. Uther Pendragon, Arthur's father, is disguised as the Duke of Cornwall, Golois, with Merlin's help in order to sleep with the duke's wife, Igraine. Later, Igraine gives birth to Arthur and Merlin takes the child and puts him in the care of Sir Ector. Merlin also seals the legendary sword Excalibur in stone so that only the rightful heir to the throne may remove it.
Once Arthur withdraws Excalibur and becomes the king of England, Merlin serves as the king's advisor.