Lantern oaths. White, whose oath has not yet been spoken, represent life. Red is rage. Orange is avarice. Yellow, the Sinestro Corps, is fear. Green is willpower. Blue is hope. Indigo tribe (oath spoken and written in native tongue) is compassion. Star Sapphires wield love. Black represent death.
John Steward. The third human Green Lantern. Became Hal Jordan's temporary back-up, when Guy Gardener was injured. Has a belligerent attitude to authority figures, which Hal Jordan didn't like, but the two soon became friends. Good.