Tim the Enchanter comes from a character played by John Cleese in the Monty Python movie Monty Python and the Holy Grail. In it, Tim causes three fiery explosions then teleports up to our heroes, which prompts the following exchange:
Arthur: What manner of man are you that can summon up fire without flint or tinder?
Tim: I... am an enchanter.
Arthur: By what name are you known?
Tim: [deadpan] There are some who call me... "Tim"...?
Arthur: ...greetings, Tim the Enchanter.
Tim leads them to the vicious Rabbit of Caerbannog, which gets blown to tiny bits by the holy hand grenade of Antioch.
Legend has it that Tim was named for Tim Brooke-Taylor. Cleese chose to play Tim with a Scottish accent for no apparent reason.