Merlin

Became the manservant of Prince Arthur
Had to hide his magical abilities, due to Uther Pendragon’s band of all magic
Saved Arthur several times from peril by secretly using his magic
Befriended one of the last Dragons, whom he often went to for advice
Help Arthur reunite the kingdom of Albion by uniting the Old Ways with the new
Would something disguise himself as an 80 year old man named Emrys
Eventually revealed his magic to King Arthur, strengthening their friendship
Brought a mortally wounded Arthur to Avalon, told that Arthur would rise again
Centuries later, lived as an elderly vagabond in the modern world wait for Arthur’s return