Old Nick
or
"Auld" Nick is one of the many
slang terms or
appropriately enough,
nicknames for
the devil,
Satan,
Lucifer or whatever you are most
familar with.
The story goes that the Archangel Sammael, first of the Heavenly Host rebelled against God when God placed Adam above the angels in the Order of Creation. Sammel, also called Lucifer Morningstar and the most beautiful of all angels proceeded to war against God.
He was defeated and fell, to become Lord of Hell.
This story is best recounted (in my opinion) in Paradise Lost by the blind poet, John Milton.