Green Lantern is a name that has been used by many characters in the DC Universe, and two distinct franchises. The original during the Golden Age was businessman Alan Scott, who wore a magic power ring that created energy constructs and had to be charged using his mystic lantern. "Green Lantern" was reimagined in the Silver Age as test pilot Hal Jordan, a member of an intergalactic peacekeeping force called the Green Lantern Corps. The Guardians of the Universe on Oa give these Lanterns rings controlled by willpower, and send them to patrol all 3600 sectors of the known universe. Jordan was said to be a member of the Justice League on Earth-One, and Scott was said to be a member of the Justice Society on Earth-Two. Their timelines were merged during the Crisis on Infinite Earths, and it was explained that Scott's magic ring taps into the Starheart.
There have been several other human Green Lanterns of Sector 2814. The brash Guy Gardner and later the architect John Stewart were both originally introduced as replacements for Jordan. Kyle Rayner became the fifth and only Green Lantern when Jordan turned into the evil Parallax and destroyed the Corps during Emerald Twilight. The Corps has since been rebuilt with all Lanterns serving simultaneously. Muslim engineer Simon Baz would become the sixth. PTSD victim Jessica Cruz became the seventh after inheriting the Ring of Volthoom from Power Ring of the Crime Syndicate. The Alan Scott version of Green Lantern was created by Bill Finger and Martin Nodell, first appearing in All-American Comics #16. (1940) The Hal Jordan version was created by John Broome and Gil Kane after an initial concept by Julius Schwartz, first appearing in Showcase #22. (1959)